Australia: New Zealand's self-colliding "poisonous" divisional application – a timely reminder

Last Updated: 17 October 2016
Article by Gareth Dixon

New Zealand's Patents Act 2013 took effect from 13 September 2014. Among the many changes brought about by the new legislation was the way in which the prior art base was defined. In combination with the fact that a New Zealand patent claim is afforded a single priority date only, this potentially gives rise to a perfect storm of self-colliding (or "poisonous") divisional applications. At present, it is uncertain whether this scenario has come about by accident or design. However, a few pointers are now beginning to emerge.


New Zealand's Patents Act 2013 (the "new Act") has been in force now for a little over two years. Given that it takes on average (allowing for an appropriate degree of generalisation) about two years for a New Zealand patent application filed under the new Act to move from filing to acceptance, it is conceivable that many of the earliest-filed new Act cases will very soon be approaching their respective acceptance deadlines.

In respect of New Zealand practice, which requires that a divisional application is filed before its immediate parent is accepted, patentees have – or will soon have a decision to make: should we file a divisional? There are several reasons why filing a divisional application makes good strategic sense: unity, flexibility, a defensive position and a desire to seek greater/different claim scope being just some of them.

Divisionals under the Patents Act 1953

Previously, under the Patents Act 1953 (the "old Act"), New Zealand divisional practice was somewhat patentee-friendly. The requirement to file a divisional before the parent was accepted still existed. However, there was no restriction on the facility to "daisy chain" as many successive divisionals as the patentee desired. This has, of course, changed under the new Act such that a five-year limit has been imposed (i.e., no divisionals in a series can be filed after five years has elapsed from the filing date of the earliest ancestor application).

Introducing the self-colliding "poisonous" divisional

The fact that a New Zealand claim can have only the one priority date gives rise to some potential problems – especially when combined with the way in which the "prior art base" is defined under the new Act. Perhaps the most significant of these is known as the "self-colliding" or "poisonous" divisional. This concept has gained a fair amount of notoriety recently by way of the UK Patents Court decision in Nestec S.A. & Ors v Dualit Ltd & Ors [2013] EWHC 923 (Pat) (22 April 2013). The general concept at play is that where a claim in a divisional application is not entitled to the earliest priority date of its parent, it can then be anticipated by its parent.

The reverse situation is also true – a divisional application can anticipate its parent in cases where claims of a relatively broad parent application are not entitled the earliest priority date, but the relatively narrow claims of a later-filed divisional are.

It should be appreciated that the New Zealand situation does not directly mirror that of the UK because, under New Zealand law, provisional patent applications are not taken to form part of the prior art base. Conceptually, however, the notion of self-collision based upon the recent UK case law appears alive and well under the provisions of New Zealand's new Act.

Under the old Act, members of the same patent family (e.g., a parent application and one or more divisional applications) needed only comply with the "prior claiming" provision and, in particular, section 14 of the old Act. This provision was somewhat narrow and intended primarily to prevent double patenting. By comparison, under the new Act, there has been adopted a "whole of contents" test for novelty. It is this definition that enables the threat of self-collision between a divisional application and its parent, and vice versa.

The potential for self-collision is heightened by the new Act requiring that the description within the patent specification adequately "supports" the claims. This is a higher standard than the "fair basis" requirement specified under the old Act. As such, any claim governed by the new Act will be more susceptible to forfeiting one or more of its priority claims (remembering that only a single priority date is allowed), which in turn, opens to door to the threat of a self colliding, poisonous relationship with its parent application.

Legislative accident or legislative intent?

It can be argued that the potential for self-collision is not simply an artefact of the way the new Act is drafted and that it is actually consistent with the intent of the new legislation. The draft legislation, dating back to late 2004, previously contained an "anti self-collision" clause attached to the definition of the prior art base, in order to prevent a divisional application anticipating its parent, or vice versa. However, this clause was then removed by the New Zealand Government during the final stages in the passage of the new Act.

On the one hand, the removal of the anti self-collision provision from the new legislation seems consistent with the overall tenet of the new Act. For example, throughout the new Act, the onus is increasingly being placed upon the patentee to "plant their flag" as quickly and definitively as possible. This onus should provide, relative to old Act applications, an increased degree of certainty to third parties from a very early stage in the patent process. As such, one could speculate that it was the intention of the legislature to provide a re-balance between the interests of patentees and third party interests.

On the other hand, the anti self-collision clause may have been removed to gain greater conformity with international norms. For instance, the corresponding clause had not been well received during negotiations toward the WIPO draft Substantive Patent Law Treaty (SPTL), which ran concurrently with the early stages of patent law reform in New Zealand. Indeed, Australia – New Zealand's closest trading partner, lacks any such provision in its Patents Act 1990. On the other hand, it should be noted that patent claims in Australia are allowed more than one priority date; an anti self-collision clause would likely be redundant on this basis.

Thus, whilst the removal of an anti self-collision provision from the new Act may have been intentional, the potential consequences of such removal may not have been. To this end, we note the publicly-accessible dialogue between the New Zealand Law Society and the Ministry of Business, Innovation, and Employment (the Government Department responsible for administering the new Act) toward a possible amendment to the new Act to clarify the situation.

How could the Government correct poisonous priority (assuming it wanted to)?

If the New Zealand Government was to decide that poisonous priority should be removed, then the "fix" is actually fairly quick and easy. Indeed, New Zealand need look no further than many of its closest trading partners. For example, the United States and Japan have anti self-collision provisions in their respective patent laws; and Australia and Europe allow a claim to have multiple priority dates. Both solutions are available to the New Zealand Government should it perceive that poisonous priority is indeed an issue.

Prediction: Poisonous priority is here to stay

At present, the New Zealand Government is in the midst of what would be its quickest and easiest avenue to correct the poisonous priority situation, should it wish to. Specifically, the Patents (Trans-Tasman Patent Attorneys and Other Matters) Amendment Bill is presently awaiting its second parliamentary reading (we have reported on this legislation previously, within the guise of the Trans-Tasman "Single Economic Market" reforms and their likely abandonment).

As suggested in the section heading above, we do not see New Zealand's position with respect to poisonous priority changing any time soon; if the Government wanted it removed, there would be, by this stage of the legislative process, clear indications that this was on the cards. There aren't.

Specifically, the issue of poisonous priority was raised in a number of submissions made to the Commerce Select Committee during the earlier public consultation phase of the Amendment Bill. However, when the Committee released its recommendations on 13 July 2016, poisonous priority did not so much as rate a mention. Accordingly, it is difficult to envisage how a "fix" to this perceived issue could now be installed within the draft legislation before such time as it is passed.

Another reason why we feel that poisonous priority is here to stay was that when the anti self-collision clause was removed from the new Act by the very same Commerce Select Committee, this was done on that back of a single public submission having no reasoned analysis behind it. It is therefore possible that there were other forces at play here – and the above-mentioned third party dimension (which is a stand-out feature of the new Act) is very possibly the reason.

Has anyone fallen foul of the poisonous priority trap yet?

To the best of our knowledge, the answer is a clear "no". This is likely the combination of a number of factors: Only a small number of new Act applications have been filed to date; of these, only a very small number of divisionals have been filed; and of these divisionals, it is reasonable to presume that a negligibly small proportion will ever have "issues" in respect of poisonous priority. In short, the sample size – both in terms of number and time, is too small for this effect to have yet raised its head in practice.

Falling foul of New Zealand's poisonous priority trap is admittedly something of a long-shot. However, mitigating risk is what this industry is all about – and presumably nobody wants to be associated with the first New Zealand divisional to collide with its parent. To this end, it is all about being aware of the risks and mapping an appropriate strategy around them.


In conclusion, New Zealand's new patent legislation requires patentees to very quickly establish and assert their patent position; there is a comparative lack of flexibility here which could be considered unduly restrictive.

What is clear, however, is that the new Act no longer allows patentees to use the divisional facility as a last minute bail out option. It does provide a divisional facility (out to the five year limit as discussed above) – but the threat of poisonous priority requires that from a strategic perspective, any consideration of whether to file, or not to file a new Act divisional application is best performed in conjunction with a New Zealand patent attorney who will be apprised of the risk/reward balance in venturing down this particular path.

Shelston IP's patent attorneys are registered to practise in both Australia and New Zealand and are well versed in the laws and practices in both jurisdictions. Any reader having a New Zealand patent application who requires specific advice to supplement the general commentary provided above, should contact their Shelston IP patent attorney, or the author of this article.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

Shelston IP ranked one of Australia's leading Intellectual Property firms in 2015.

To print this article, all you need is to be registered on

Click to Login as an existing user or Register so you can print this article.

Some comments from our readers…
“The articles are extremely timely and highly applicable”
“I often find critical information not available elsewhere”
“As in-house counsel, Mondaq’s service is of great value”

Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:
  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.
  • Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.
    If you do not want us to provide your name and email address you may opt out by clicking here
    If you do not wish to receive any future announcements of products and services offered by Mondaq you may opt out by clicking here

    Terms & Conditions and Privacy Statement (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

    Use of

    You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


    Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

    The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


    Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

    • To allow you to personalize the Mondaq websites you are visiting.
    • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
    • To produce demographic feedback for our information providers who provide information free for your use.

    Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

    Information Collection and Use

    We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

    We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to with “no disclosure” in the subject heading

    Mondaq News Alerts

    In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


    A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

    Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

    Log Files

    We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


    This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

    Surveys & Contests

    From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


    If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


    From time to time Mondaq may send you emails promoting Mondaq services including new services. You may opt out of receiving such emails by clicking below.

    *** If you do not wish to receive any future announcements of services offered by Mondaq you may opt out by clicking here .


    This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to

    Correcting/Updating Personal Information

    If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to

    Notification of Changes

    If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

    How to contact Mondaq

    You can contact us with comments or queries at

    If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at and we will use commercially reasonable efforts to determine and correct the problem promptly.

    By clicking Register you state you have read and agree to our Terms and Conditions