Australia: Exploring standard lease terminology: What are best endeavours and reasonable endeavours? And when should you use them?

Last Updated: 19 November 2014
Article by Steven Askew
Focus: Assessing the implications of a party having to use 'best endeavours' or 'reasonable endeavours' to achieve a particular contractual objective
Services: Property & projects
Industry Focus: Property

During a lease negotiation, have you ever been unable to agree on the terms for delivery of a crucial measure that is intended to get the landlord-tenant relationship off to a positive start (such as obtaining development consent for the proposed use)?

In this, the third instalment of our three part series examining standard lease terminology, we assess the implications of a party having to use 'best endeavours' or 'reasonable endeavours' (and variations on that theme) to achieve a particular contractual objective.

Commercial parties view these expressions as an expedient means of resolving deadlocks in negotiations over absolute obligations to achieve a contractual objective. Accordingly, it is important to understand these expressions, and which might best be used in the circumstances.

The established meaning of 'Best Endeavours' and 'Best Efforts'

An obligation to use 'best endeavours' (or the interchangeable 'best efforts') to achieve a contractual objective has an established meaning as a result of the cases in which that term has been considered. In the leading case of Hospital Products Ltd v United States Surgical Corporation, Gibbs CJ of the High Court held that an obligation to use 'best efforts' necessarily includes an obligation not to hinder or prevent the fulfilment of the purpose of the contract, but did not require the person undertaking the obligation to go beyond the bounds of reason.

Later decisions such as Hawkins v Pender Bros Pty Ltd and Centennial Coal Company Ltd v Xstrata Coal Pty Ltd emphasise that a party's obligation to use 'best endeavours' requires it to exhaust all courses of action to the point where the prospects of success are so remote that further endeavours would be wasted. Even where there is apparently no realistic chance of achieving the contractual objective, the obligated party may have to wait to see if circumstances change to allow the objective to be achieved.

These observations mean that, if a person is obliged to use 'best endeavours' to achieve a contractual objective and their first reasonable effort fails, they may be required to take further action, if other options with a reasonable chance of achieving that objective still exist. However, a course of action will not fall within the scope if it undermines a party's commercial standing or may lead to financial ruin.

'Reasonable Endeavours' and 'All Reasonable Endeavours'

It is not clear whether an obligation to use 'reasonable endeavours' to achieve a contractual objective is less onerous than an obligation to use 'best endeavours'. In Electricity Generation Corp v Woodside Energy Ltd, the High Court did not have to decide this question but noted that the case proceeded on the basis that 'substantially similar obligations are imposed by either expression'.

Writing in his personal capacity, Lewison LJ of the English Court of Appeal has suggested that 'reasonable endeavours' requires a party to take a reasonable course of action to achieve the contractual objective (but not all reasonable courses, thereby affording the obligor freedom to choose the most suitable course for them or their business), whereas an obligation to use 'best endeavours' requires a party to take all reasonable courses possible. There is some support for this in the Australian case law. In Stepping Stones Child Care Centre (ACT) Pty Ltd v Early Learning Services Ltd, Refshauge J of the ACT Supreme Court held that 'reasonable endeavours' is a lesser standard than 'best endeavours'. In Woodside Energy, the High Court observed that the nature and extent of an obligation imposed in such terms is necessarily conditioned by what is reasonable in the circumstances, which can include circumstances that may affect an obligor's business.

On the face of it, one would think that there would be little (if any) difference between an obligation to use 'reasonable endeavours' and an obligation to use 'all reasonable endeavours'. However, a series of cases in the New South Wales Court of Appeal culminating in the decision in Centennial Coal Company Ltd v Xstrata Coal Pty Ltd suggest that an obligation to use 'all reasonable endeavours' is substantially similar if not identical to the obligation to use 'best endeavours'. The point remains undecided by the High Court, and until a decision is reached, it would be best to avoid using the term 'all reasonable endeavours'.

When in doubt, spell it out

It is always open to the parties to prescribe in their contract either what is meant by any of the terms discussed above or what is excluded from the scope of any of these terms. This allows the parties to identify what is covered by an obligation to use 'best endeavours' or 'reasonable endeavours' to achieve a contractual objective, rather than leaving it to a court to do so.

Lessons and pointers to note

The following lessons and pointers emerge from the cases.

  1. 'Best endeavours' is well understood in the case law to mean all courses of action. If you are unwilling or ill-equipped to exhaust all courses of action in trying to achieve the contractual objective, it would be prudent to specify what actions are excluded from the 'best endeavours' standard.
  2. 'Reasonable endeavours' remains a viable alternative to 'best endeavours'. Although it is not as well understood in the case law as yet, it may give you the latitude to decide which course of action best suits you from a commercial perspective.
  3. The term 'all reasonable endeavours' is best avoided as it may be confused with 'reasonable endeavours'. If you must use 'all reasonable endeavours', it would be prudent to specify what actions are excluded from the 'all reasonable endeavours' standard.

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.

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”

Mondaq Advice Centre (MACs)
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
Check to state you have read and
agree to our Terms and Conditions

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.

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 by clicking here .

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.


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.