Australian patent law provides a relatively low-cost (pre-grant) procedure to oppose grant of a patent, on various grounds, by filing a Notice of Opposition within 3-months of the date of publication of acceptance. Once initiated, an opposition procedure is conducted before the Australian Patent Office.
Evidence is Pivotal
Importantly, Australia's patent opposition procedure entails an evidentiary phase during which expert evidence is prepared and submitted by the opponent and the patent applicant. That evidence may comprise declarations by one or more experts setting out their opinions on, amongst other things, the disclosure of prior art references and the scope of the claims of the patent specification of the opposed application.
At the conclusion of the evidentiary phase, an inter-partes hearing is conducted leading to a decision on the outcome of the opposition. That decision depends, to a large extent, on the evidence filed prior to the hearing.
Timing for Filing Evidence
As a result of revised opposition requirements adopted in April 2013, the time periods for completing the different stages of the opposition procedure are more rigid and strictly enforced.
In particular, within 3-months of filing the Notice of Opposition, the opponent must submit their statement of case setting out the grounds and particulars on which the opposition is based. This statement, called the "Statement of Grounds and Particulars", amongst other things, identifies relevant prior art documents and/or prior use activities intended to be relied upon, and particularises the relevance of those documents or use activities to the validity of the claims of the opposed application.
Within 3-months of filing the Statement of Grounds and Particulars, the opponent is then required to prepare and file "Evidence in Support" comprising their expert's declaration(s) and supporting material. The applicant then has a period of 3-months, beginning after the "Evidence in Support" has been filed, to prepare and submit their "Evidence in Answer" responding to the "Evidence in Answer".
As a final step prior to the hearing, the opponent is provided with a further 2-month period, beginning after the "Evidence in Answer" has been filed, to prepare and submit "Evidence in Reply" which responds to the "Evidence in Answer".
Gathering and compiling expert evidence is a complicated activity requiring careful management of evidence preparation activities and planning to avoid steps which may otherwise jeopardise the opposition process. In some circumstances, despite the best efforts of the attorney responsible, such complications and considerations, when combined with limited availability of experts, can present challenges in finalising evidence within the required periods. In such cases, further time may be needed, but difficult to obtain via an extension of time.
Extensions of Time
Whereas prior to April 2013, extensions of time were available (and frequently relied upon), under the revised requirements extensions of time for completing the different stages of an opposition are not readily available, and may instead only (potentially) be available in particular circumstances. As a result, extensions of time to, for example, file Evidence in Support, have proven difficult to obtain. Despite the stricter enforcement of extension of time provisions, opponents and applicants are nevertheless continuing to apply for extensions of time to prepare and submit evidence, with varying degrees of success.
Public Interest Considerations
If evidence is not completed by the relevant date, and if an extension of time either has not been applied for or is refused, an additional opportunity to bring evidence into an opposition may be available via Regulation 5.23 of the Patent Regulations.
Regulation 5.23 was introduced as a part of the new patent procedural requirements in April 2013 and provides the ability for the Commissioner to retain a discretion to rely on documents that are not formally in evidence in order to protect the public interest. At the time of introduction of the new requirements, an Explanatory Statement  provided the following guidance as to extent of the discretionary type applicability of Regulation 5.23:
Regulation 5.23 may thus allow the Commissioner to consider "new" information even in circumstances where the information has been submitted outside the evidence periods.
In recent opposition decisions, the Australian Patent Office has interpreted the above statement and regulation 5.23 as requiring regard to the nature of the "new" information and whether the information is likely, if not certain, to change the outcome of the opposition in a significant way. If the new information is likely to so change the outcome of the opposition, then it appears that the Patent Office may allow such information to be filed outside of the evidentiary periods and considered during the opposition.
In the first Patent Office decision  to consider the application of Regulation 5.23, the required relevance of the information was considered in the context of an overlap between the applicability of that regulation and Australia's re-examination provisions:
In a series of decisions involving Innovia Security Pty Ltd as an opponent, the applicability of Regulation 5.23 has been further considered and applied to allow the opponent to submit new information, in the form of further evidence, outside the evidentiary phase.
In a first decision  involving Innovia Security Pty Ltd, the new information included a prior art document considered "... paramount to Innovia's case on alleged anticipation, and from a preliminary assessment of its relevance it seems that reliance on document D1 may well change the outcome of the opposition in a significant way...".  In this case, the discretion provided by regulation 5.23 was applied and the information considered.
In a subsequent and unrelated decision , involving the same opponent, the new information included a declaration intended to establish the publication date of a previously exhibited document which included information considered "significant, and indeed potentially pivotal, in the determination of the grounds of inventive step" . Once again the discretion was applied and the information considered.
In a third decision , also unrelated, the opponent relied on Regulation 5.23 again, this time to bring two new documents into opposition proceedings (prior to the hearing) which were considered "relevant to the grounds of novelty and inventive step" . Here again, the Commissioner applied her discretion under regulation 5.23 and allowed the information to be considered.
In each of the decisions involving Innovia Security Pty Ltd, none of the grounds for opposition were successful and thus it would seem that the new information considered under Regulation 5.23 did not change the outcome of the opposition.
Only Time Will Tell
Regulation 5.23 may provide an opportunity to have new evidence brought into an opposition in circumstances where the new evidence includes information which is more relevant to the grounds of novelty and inventive step than information previously exhibited, or substantiates facts associated with information already under consideration. Given the tightened extension of time provisions which apply to obtaining additional time to file evidence, it remains to be seen to what extent Regulation 5.23 will be relied upon as a de facto approach for obtaining an extension of time to file evidence.
 Explanatory Statement, Select Legislative Instrument 2013 No. 31, Issued by the Authority of the Minister for Industry and Innovation
Ibid at page 21
 Merial Limited v Bayer Intellectual Property GmbH  APO 16 (14 April 2015)
 Ibid, paragraph 22
 Innovia Security Pty Ltd v De La Rue International Limited  APO 31 (25 June 2015)
 Ibid at paragraph 25
 Innovia Security Pty Ltd v OVD Kinegram AG  APO 26 (17 June 2015)
 Ibid at paragraph 7
 Innovia Security Pty Ltd v OVD Kinegram AG  APO 46 (6 August 2015)
 Ibid at paragraph 2
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.