Hallucinated citations and the duty to the court.

Australian courts have now dealt with a steady series of matters in which practitioners filed submissions citing authorities that do not exist. The Law Society of NSW guide names the pattern plainly: generative AI can produce fictitious case law and references that appear legitimate, known as hallucinations, and no current tool is free of them. Solicitors who file unverified AI output are not making a technology mistake; they are breaching duties that predate the technology by a century.

The cases that made it concrete

The guide cites the American case that started the genre, Mata v Avianca, Inc., and Australian matters including Dayal [2024] FedCFamC2F 1166 and Murray on behalf of the Wamba Wemba Native Title Claim Group v State of Victoria [2025] FCA 731. In one Victorian instance, filing hallucinated authorities led to regulatory action against the practitioner’s practising certificate. In another matter discussed in the guide, the court found a junior solicitor had taken insufficient care checking citations, and that her supervisor’s failure to supervise contributed to the error, which is why this page and our supervision guide are really about the same obligation viewed from two seats.

The rules doing the work

Rule 19 requires that solicitors not mislead the court, even inadvertently; rule 4.1.2 requires honesty and competent, diligent delivery of legal services. The guide draws the operational conclusion: solicitors using AI to prepare documents must be able and qualified to personally verify the contents, and must actually do so. Court practice notes now add procedural teeth in several jurisdictions, including the Supreme Court of NSW’s practice note on generative AI (Supreme Court of NSW), and the guide directs practitioners to comply with the practice notes applicable in each court.

Verification is the job, whatever the tool

The guide recommends preferring tools that let the user interrogate the sources behind an output. That is good procurement advice, and it changes nothing about the duty: every authority gets checked against the primary source before it is cited, whoever or whatever drafted the document. A workflow that treats AI output like the work of a capable junior, useful, fast, and unverified until a qualified person has checked it, satisfies the rules. A workflow that treats it as finished work does not.

Where deployment posture fits

An on-premise unit narrows the fabrication surface for firm knowledge, because drafting is grounded in the firm’s own indexed documents, precedents and files rather than a model’s general recall, and the source material sits one click away for checking. It does not change the verification duty for legal authority, and nothing does: case citations get verified against the law reports by a qualified person, on every matter, with any tool.

Common questions