7 October 2025
Written by George Sassine
The Harman undertaking is a fundamental principle in Australian law that governs the handling of documents obtained from or during a court process. It is a substantive legal obligation that compels all parties to use documents and information obtained through compulsory litigation processes like discovery or subpoenas, only for the purpose in which of the legal proceeding in which required their disclosure.
The undertaking is an implied one that was first derived from the seminal case of Harman v Secretary of State for Home Department [1983] 1 AC 280 (Harman). Harman was then solidified as an implied undertaking in a case in the High Court of Australia in Hearne v Street (2008) 235 CLR 125.
As noted above, the undertaking serves an important purpose, that is, to protect the privacy of those who are compelled to disclose sensitive information during the course of litigation. In this article we outline the key aspects of the undertaking, its implications for legal practitioners and their clients as well as provide practical steps for navigation this sometimes-overlooked critical obligation.
The Harman undertaking applies broadly to a wide range of material including copies of any information derived from them. This includes:
Here, a crucial distinction exists for affidavits as the undertaking only applies when a party is ordered to produce the document. If an affidavit is voluntarily filed in Court, and or relied on in open Court, in accordance with routine timetable orders, it is generally not subject to the undertaking as the filing of the affidavit part of open Court has been done so voluntarily. This obligation not only binds the parties to the litigation but also their legal practitioners, and any third party who receives the documents and is aware of their origin in a legal proceeding.
It is also important to note that not being aware that the information or documents form part of a legal proceeding or had their origin in a legal proceeding will not constitute a defence to breaching the undertaking.
Using these disclosed documents for a purpose other than within the scope of the proceedings is considered a breach and should be avoided at all costs.
In many cases a breach can be considered contempt of court and can have serious repercussions on not only a client’s case, but for your client but also for the legal practitioner who may be alleged to have breached the Harman undertaking.
Examples of how the documents can be used to constitute a breach are as follows:
While the undertaking can seem like an imposition on open justice, it does exists to ensure that parties are encouraged to make full and frank disclosure knowing that The other party is bound by an undertaking not to misuse that information.
Practitioners and clients are able to take simple and easy steps to navigate the undertaking responsibly. Some useful examples of these non-exhaustive steps include:
Finally, in exceptional circumstances, practitioners are able to seek leave to be released from the undertaking. To do so, the party must make an application with the Court that the documents or information where produced . The decision will be made by the Judge or officer who is presiding over the matter.
Usually, any applicant seeking a release from the undertaking most show exceptional circumstances and the decision to have a party be released is discretionary in nature.
We hope this article provides a succinct overview and useful insights into the Harman undertaking and how best to navigate it.
There is no doubt the Harman undertaking is an important piece of the Australian legal system.
By working to understanding its scope and what to be aware of when dealing with crucial documents, practitioners and also their clients can ensure they are not running afoul of the principle while also upholding the integrity of the Australian judicial process.
Sources
Cases
Harman v Secretary of State for Home Department [1983] 1 AC 280
Hearne v Street (2008) 235 CLR 125
Legislation
County Court Civil Procedure Rules 2020 (Vic), R29.01 – 29.15
Supreme Court (General Procedure Rules) 2015 (Vic), R 29.01.1
Secondary
A Criminal Lawyer’s Brief Guide to The Harman Obligation, Richard Pontello SC, Sir Owen Dixon Chambers, March 2021 – https://publicdefenders.nsw.gov.au/documents/news-and-publications/conferences/past-conference-material/2021/richard-pontello-sc-harman-1.pdf\
The Harman Undertaking, Bond University and Andrew Berger KC – https://actls.bond.software/publicassets/61547125-097b-ef11-9124-00505687f2af/Harman%20obligation%20presentation.pdf
The Implied Undertaking Rule, Monash University Law Review (Vol 34, No 1), Robert Williams, 2008 – https://classic.austlii.edu.au/au/journals/MonashULawRw/2008/6.pdf
The Harman Undertaking and Tax Litigation, Wentworth Chambers, 2023 – https://www.wentworthchambers.com.au/wp-content/uploads/2023/12/The-Harman-Undertaking-and-Tax-Litigation-20181019102423.pdf