Beyond courtroom advocacy, criminal law will always primarily rely on a foundation of evidence. A subpoena is an essential building block to that foundation but is a court order very few know about. Essentially, they compel parties to produce evidence, or attend court, but a host of rules governs them.
Criminal Defence Lawyers Australia recently won an appeal in the NSW Court of Criminal Appeal about an accused person’s right to subpoena material for their defence. In RS v Commissioner of Police (NSW) [2026] NSWCCA 128, the Court overturned a District Court decision that had set aside a subpoena, finding the material sought had an obvious legitimate forensic purpose and ordered NSW Police to produce it.
This article will explain how subpoenas work in criminal proceedings, the decision in RS, what it means for accused people, and criticisms of the current law.
What Is a Subpoena?
A subpoena is a court order requiring a person or organisation to produce documents or things to the court, attend court to give evidence, or both. Failing to comply without a lawful excuse can be punished as contempt of court.
In criminal proceedings, subpoenas let an accused person obtain evidence held by others, such as police, phone, social media, internet search or medical records. In NSW, they are governed by the Criminal Procedure Act 1986 and each court’s rules.
The prosecution have disclosure obligations and must disclose material that is relevant or possibly relevant to the criminal proceedings, or that may provide a lead on evidence: R v Reardon (No 2) (2004) 60 NSWLR 454 at [48]. A subpoena lets the defence seek material the prosecution does not hold or has not handed over.
The “Legitimate Forensic Purpose” and “On The Cards” Requirements for Subpoenas
A party issuing a subpoena must have a “legitimate forensic purpose” for the material sought. A subpoena cannot be used for a “fishing expedition”, issued in the hope that something useful might turn up: Alister v The Queen (1984) 154 CLR 404 at 414. If no legitimate forensic purpose exists, the subpoena may be set aside as an abuse of process. Anything which might disclose evidence for proper and fruitful cross examination will generally constitute a legitimate forensic purpose. In a civil case, the NSW Court of Appeal held it is generally enough that the documents are apparently relevant to the issues: Secretary, Department of Planning, Industry and Environment v Blacktown City Council (2021) 118 NSWLR 336 at [65].
Whether the more generous civil approach also applies in criminal cases has not been settled.
Further to the requirement of satisfying a “legitimate forensic purpose”, the material sought in the subpoena in question must also be what the law refers to as “on the cards” that it will materially assist the defence case- in respect of a subpoena issued by the defence or defendant. It will generally be considered “on the cards” if it appears to be “on the cards” that the material sought will materially assist the case or it will materially assist on an identified issue even if the information sought is not ultimately found to be admissible in evidence- this is what was explained in the case of Alister v The Queen (1983) 154 CLR 404 and R v Saleam [1999] NSWCCA 86 at [11]. The Subpoena must also specify the materials sought with “reasonable particularity” and must not be a “fishing expedition”.
The Supreme Court Decision of RS v Commissioner of Police (NSW)
In September 2024, RS (a pseudonym) was charged with Commonwealth offences relating to child abuse material found on his mobile phone. He pleaded not guilty. His case is that the central issue at trial is whether it was him, or someone else, who accessed the material.
In May 2026, the Commonwealth Director of Public Prosecutions (CDPP), complying with its disclosure obligations, gave RS material about separate charges against his son, RJ (also a pseudonym), for alleged child sexual offences. RJ worked with RS and had an opportunity to access his phone.
RS obtained leave to serve a subpoena on the NSW Commissioner of Police for RJ’s brief of evidence and related police (COPS) records. The Commissioner applied to set it aside for lack of a legitimate forensic purpose, arguing the alleged offending was of a different nature and no devices had been seized from RJ.
On 22 May 2026, the District Court set the subpoena aside. The judge found it was not “on the cards” that the material would help establish that RJ had a sexual interest in child abuse material, describing the request as “an exercise in speculation”. RS’s trial, due to start on 28 May 2026, was vacated so he could appeal.
On 28 August 2026, the Court of Criminal Appeal (Chen J, with Mitchelmore JA and Sweeney J agreeing) allowed the appeal and ordered police to produce the material by 4 September 2026. It identified three errors.
The first was that RS argued the material would show RJ had a sexual interest in children, not in child abuse material. The Court said that was “appreciably less demanding” to establish, and the District Court had assessed the wrong question: [43]–[44].
Further, the CDPP’s disclosure should have been the “starting point” of the inquiry: [49]. It could only have been made because, on a sensible appraisal, the material ran counter to the prosecution case or might help the defence. This was “powerful evidence – from the prosecuting authority, no less” that a legitimate forensic purpose existed: [50].
Finally, only differences were considered. Differences between the alleged offending were “relevant, but not dispositive”: [51]. The District Court overlooked a key similarity, an alleged sexual interest in young girls. Its premise that a person accused of assaulting a child could have no other sexual interest in young girls was “counter-intuitive” and “heterodox”: [52]–[53].
The Court held a legitimate forensic purpose existed whichever formulation applied, because the material had “obvious evidentiary value” and “could well be vital” to RS’s defence: [55].
The decision gives practical guidance on how courts should approach a challenge to a defence subpoena:
Where the prosecution has disclosed material under its obligations, that is strong evidence that related material has a legitimate forensic purpose. Further, a court must test the forensic purpose the accused puts forward, not a narrower or harder version of it. The Court also noted the inquiry should not be unduly restrictive and that a party is “entitled to build up an evidentiary mosaic”: [56], citing Lakatoi Universal Pty Ltd v Walker [1998] NSWSC 470.
The law on subpoenas draws criticism from both sides.
The primary criticism is around the tests still remaining unclear. Five years after Blacktown City Council, the Court of Criminal Appeal has not decided whether its more generous approach applies in criminal cases. An accused person whose liberty is at stake may therefore face a stricter threshold than a party to a civil dispute. This is concerning since our criminal justice system necessarily must protect an accused facing the brunt of prosecution, since the consequences of conviction are so high. Examples of these protections are the raised burden of proof ‘beyond a reasonable doubt’ in criminal proceedings, and stricter evidentiary considerations under the Evidence Act 1995 (NSW).
Further, the defence must show material is likely to help without having seen it, and the line between a legitimate request and a “fishing expedition” is hard to draw. Yet the High Court has said an accused should not be left to “fossick for information” that ought to be disclosed: Grey v The Queen (2001) 75 ALJR 1708 at [23]. It seems likely that this indeterminacy is at the root of subpoenas and cannot readily be resolved.
Finally, victim-survivor advocates argue subpoenas expose private records such as counselling notes and medical files, often without warning. Legislation introduced in September 2026 would let courts consider counselling records only when necessary. Government-commissioned research due in mid-2027 will consider banning the practice outright. Any further restriction must be balanced against an accused person’s right to a fair trial, which is far from a simple equation.
A myriad of evidentiary and legal arguments can run before a matter ever gets to hearing, and subpoenas are a fundamental example that lawyers rely on. Given their necessity to court procedure, it seems likely that regulations around them are still to come.
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.
[View Source]
