Understanding Subpoenas: Avoiding Fishing Expeditions in Legal Proceedings

Litigation: 16 June 2026

Author: Joel Parsons - Our People

Subpoenas are a powerful tool in litigation but if used improperly, they can be challenged as “fishing expeditions” and set aside by the court. Understanding their proper use is critical to ensuring your requests serve a legitimate forensic purpose.

If you were to go fishing, one of the last tools that you would think to use is a subpoena. However, in the legal sphere, it is much more common than you might think.

This article explores the legal concept of subpoenas and their proper use in court proceedings, with a particular focus on the risks of so-called “fishing expeditions.” We’ll explain what a subpoena is, when and how it can be used, and why courts carefully scrutinise requests that may be too broad or speculative. By examining recent case law and established legal principles, you’ll gain a clear understanding of how to avoid improper subpoena practices and ensure your requests have a legitimate forensic purpose.

What is a Subpoena?

If you are well versed in the law or have ever seen an episode of the hit TV show Suits, you have likely heard the term ‘subpoena’ being used. A subpoena is a legal document issued by a court at the request of a party to a proceeding. A subpoena can serve many functions, including to compel a party to:

• give evidence;
• produce documents; and
• attend court to do both of the above.

Proper Use of Subpoenas in Legal Proceedings

Subpoenas are required when a party is unwilling or unable to meet a request voluntarily. Although subpoenas are often an effective way to obtain information, there are strict rules governing both their service and use. Subpoenas cannot be addressed to more than one person, and they must to identify the documents to be produced, specifying the time, date, and place of production.

Subpoenas also cannot be used for an improper purpose, the most common example of which is what is known as a ‘fishing expedition’.

Fishing Expedition

A subpoena may be characterised as being used for a ‘fishing expedition’ where it is seeking production of documents that go beyond the scope of the issues raised in the proceedings. The production of documents should be done so for a “legitimate forensic purpose”, and should not extend beyond such purpose. If they do, the argument that flows as a result is that such documents should not be produced because, put simply, they are irrelevant.

A subpoena can also be characterised as a fishing expedition if there is no apparent basis for determining that any documents sought by the subpoena could impact the case of any of the parties.

Court’s Findings on Improper Subpoena Use

Vissell & Vissell [2021] FamCAFC 76

In Vissell, the Full Court of the Family Court of Australia allowed an appeal against the dismissal of objections to several subpoenas on the basis that they extended beyond the legitimate forensic purpose, thereby constituting a ‘fishing expedition’ and being oppressive to the party compelled.

It was determined that, before an order was granted for the documents to be addressed:

1. A legitimate forensic purpose must be identified; and
2. It must be established that the documents will materially assist the case “on the cards”.

Justices Ainslie-Wallace, Watts, and Tree cited Chief Justice Jordan in Commissioner for Railways v Small (1938) 38 SR (NSW) 564, noting that subpoenas must reasonably specify the documents required and cannot legitimately be used for fishing, that is, to discover whether there is a case at all, instead of obtaining documents to support the existing case.

Scope and Limits of Subpoena Requests

Carter (a pseudonym) v Australian Air League Inc [2024] VSC 95

In Carter (a pseudonym), the Plaintiff objected to a subpoena issued to Medicare by the Defendant. The issue for determination was whether the Defendant had a legitimate forensic purpose in issuing the subpoena to Medicare, which, in effect, sought the Plaintiff’s entire medical history, a submission the Plaintiff claimed was impermissibly broad.

However, His Honour Associate Judge Daly held that more targeted or confined terms would be difficult for Medicare to comply with, and although substantial medical evidence had already been provided by the Plaintiff, there were still a number of gaps in the evidence.

The above notion was appropriately expressed in Associated Dominions Assurance Society Pty Ltd v John Fairfax & Sons Pty Ltd (1955) 72 WN (NSW) 250:

“A subpoena does not constitute a fishing expedition where there are reasonable grounds to believe that fish of the relevant type are contained in the pond. That is, if it is reasonably considered that a subpoena is issued to target a specific type of fish, it will not be an expedition”.

Get in Touch: Seeking Legal Advice for Subpoenas and Litigation

If you require assistance navigating arduous litigation proceedings or are seeking general legal advice, please reach out to one of our experienced and friendly legal professionals on (03) 8600 6000.

Please note: The information in this article is provided for general information purposes only and does not constitute legal advice. It is not intended to be comprehensive or to apply to any specific circumstances. You should seek independent legal advice before acting on any information contained in this article.