Defamation Defences in Australia: The Complete List by Jurisdiction

Australian defamation law recognises a set of statutory defences, from justification and honest opinion to the newer public interest and peer review defences, but the exact list, and the section number for each, differs by jurisdiction.

This article addresses the statutory defamation defences available in New South Wales, Victoria, Queensland, South Australia, Tasmania, the ACT, the Northern Territory and Western Australia. Section numbers are given for New South Wales as the reference numbering, with variations noted where verified. It does not predict how a court would apply any defence to a specific set of facts.

The Core Defences That Exist Everywhere

Eight defences exist, in substance, in every jurisdiction covered by this cluster, including Western Australia. Justification is the defence of truth: that the defamatory imputations are substantially true. Contextual truth allows a defendant to rely on other, true imputations carried by the same matter to defeat a claim over a false one, where the true imputations mean the plaintiff's reputation is not further harmed. Absolute privilege protects publications such as parliamentary and judicial proceedings. Publication of public documents protects fair copies or summaries of specified official documents. Fair report of proceedings of public concern protects fair reports of specified public proceedings. Qualified privilege for provision of certain information protects publications made to a person with an interest in receiving the information, where the conduct of the defendant was reasonable. Honest opinion protects genuinely held opinion, rather than a statement of fact, on a matter of public interest, based on proper material. Innocent dissemination protects a subordinate distributor, such as a bookseller or broadcaster, who neither knew nor ought reasonably to have known the matter was defamatory.

The Stage 1 Additions: Public Interest and Peer Review

Two further defences arrived with Stage 1 reforms from 2021 and do not exist in Western Australia. The public interest defence, inserted at s 29A in New South Wales, protects a defendant who shows the matter concerned an issue of public interest and that they reasonably believed publishing it was in the public interest. The section directs a court to weigh a non-exhaustive list of factors, including the seriousness of the imputation, whether the matter distinguished between fact and allegation, the integrity of the defendant's sources, whether a right of reply was sought from the plaintiff, and what steps the defendant took to verify the information. The scientific or academic peer review defence, inserted at s 30A, protects a statement published in a scientific or academic journal that went through a peer review process, along with a fair copy, extract or summary of such a statement.

The Digital Intermediary Defence: A Stage 2 Addition, With a South Australian Gap

Stage 2 reforms from 2023 added a defence specific to digital intermediaries, inserted at s 31A in New South Wales, alongside a separate set of exemptions at ss 10B-10E for intermediaries providing pure caching, conduit or storage functions and for search engines over organic results. The s 31A defence is complaints-based: it protects an intermediary that operates an accessible complaints mechanism and takes access-prevention steps within 7 days of a compliant written complaint. This defence and the accompanying exemptions are in force in New South Wales, Victoria, the ACT, Tasmania, the Northern Territory and, from 26 December 2025, Queensland. South Australia is the deliberate exception. Despite adopting other Stage 2 elements, SA declined both the intermediary exemptions and the s 31A complaints defence, so a digital intermediary operating in SA has no statutory safe harbour equivalent to the other reforming jurisdictions. See online defamation in Australia for the full detail on intermediary liability, including the Voller and Defteros High Court decisions.

Triviality: Repealed Everywhere Except Western Australia

Triviality, once a defence in every Australian jurisdiction, let a defendant escape liability by proving the circumstances of publication were such that the plaintiff was unlikely to sustain harm. It was repealed outright by Stage 1 reforms, on the reasoning that the new serious harm threshold performs a similar filtering function but with the burden reversed: triviality required the defendant to disprove harm after a claim was brought, while serious harm requires the plaintiff to prove harm before the claim can proceed. Because Western Australia adopted neither Stage 1 nor Stage 2, its triviality defence at s 33 was never repealed and remains fully in force there. A defendant sued in Western Australia can still raise triviality; a defendant sued anywhere else in Australia cannot.

Defences by Section Number

Victoria and Queensland's exact section numbers for these defences have not been individually pulled from their own consolidated Acts for this guide and are assumed, on the strength of how closely their Acts track the NSW model elsewhere, to mirror the New South Wales column above. A reader who needs the precise Victorian or Queensland section number should verify it against that state's own consolidated Act before relying on it. Every other column in this table was checked directly against the relevant jurisdiction's own AustLII consolidated text.

Defences Are Not Mutually Exclusive

A defendant is not confined to a single defence and can plead several in the alternative, since each defence responds to a different element of the plaintiff's case or offers a different basis for defeating it. A publisher might, for example, plead justification on the basis that the imputations were substantially true, while separately pleading honest opinion in case a fact-finder concludes some part of the material was opinion rather than fact, and separately again pleading qualified privilege over the circumstances of publication. This layering is a routine feature of defamation litigation in Australia and reflects the reality that how a court will ultimately characterise a publication, as fact, as opinion, as privileged communication, is often genuinely contested until judgment.

Scope of Defences Preserved Under General Law

Every jurisdiction's Act includes a provision confirming that its statutory defences do not limit any defence available under the general law or another statute. This means the common law defences that predate the Defamation Acts, and any defence available under a different Act entirely, remain available alongside the statutory list above; the statutory defences supplement rather than replace the pre-existing legal landscape. This is also the provision through which cases like Lange v Australian Broadcasting Corporation (1997) 189 CLR 520 continue to matter after the uniform Acts commenced: Lange's modification of common law qualified privilege to cover political and government communication published to the public sits alongside, not inside, the statutory qualified privilege defence, and a defendant can potentially rely on either.

This article provides general legal information about the statutory defences available in Australian defamation law, verified 20 July 2026. It does not assess whether any defence would succeed on a particular set of facts. For advice on your situation, consult a legal practitioner admitted in the relevant Australian state or territory.

Related reading: the Australian defamation law hub, online defamation for digital intermediary liability, the serious harm threshold, and defamation law in Western Australia for the jurisdiction where triviality still applies.