Truth is the defence most people think of first, and the one that is hardest to run. A publisher who can prove that what it published was substantially true has a complete answer to the claim, whatever its motive and however much damage the publication caused. But the burden of proving truth sits entirely on the publisher, the standard rises with the gravity of the allegation, and a truth defence that fails often makes the eventual damages award larger. This article explains what s 25 of the Defamation Act 2005 requires, drawing on three recent Federal Court trials in which truth was the central issue.
What section 25 requires
Section 25 provides that it is a defence to the publication of defamatory matter if the defendant proves that the defamatory imputations carried by the matter of which the plaintiff complains are substantially true.1 “Substantially true” is defined in s 4 to mean true in substance or not materially different from the truth.2
Three features of the wording matter. First, the defence is directed at imputations, the meanings the publication conveys, not at the literal words. Second, it is directed at the imputations “of which the plaintiff complains”, so the plaintiff’s choice of meanings frames what the defendant must prove. Third, the defendant must prove that each of those imputations is substantially true. If one is proved true and another is not, the defence fails for the one that is not, and the defendant must rely instead on a contextual truth defence or on mitigation of damages.
The provision is identical in New South Wales, Victoria, Queensland, Tasmania and Western Australia (s 25), South Australia (s 23), the Australian Capital Territory (s 135 of the Civil Law (Wrongs) Act 2002) and the Northern Territory (s 22 of the Defamation Act 2006).3
Substantial truth and the sting
The defence does not require the defendant to prove that every detail was accurate. It requires proof that the imputation is true in substance. The High Court said long ago that every material part of the imputation must be true, but immaterial errors do not matter.4 The New South Wales Court of Appeal has explained that this does not require proof of every detail; the defence is concerned with meeting the sting of the defamation, and whether a detail is material is judged in the context of the publication as a whole.5
The practical task is therefore to identify and prove the sting of each imputation. In Lehrmann v Network Ten Pty Ltd, Lee J noted that it is sufficient if the sting or gravamen of an imputation is substantially true, and the parties agreed that the only question on truth was whether the applicant had raped Ms Higgins in Parliament House.6 On appeal the Full Court agreed that the case had been run on the basis that the sting was rape, and that once rape was established the defence was made out, even though the primary judge had not accepted the more forceful aspects of the pleaded imputations.7
The flip side is that a defendant cannot escape by proving a lesser or different meaning. If the imputation is that the plaintiff committed a crime, proving other bad behaviour will not do.
Who proves what, and to what standard
The plaintiff proves publication, identification, defamatory meaning and, outside Western Australia, serious harm. The plaintiff does not have to prove the imputations were false. The common law presumes falsity, and the onus of proving truth lies on the defendant.6
The defendant must prove truth on the civil standard, the balance of probabilities. In the Federal Court and in the states and territories with a uniform Evidence Act, s 140 requires the court, in deciding whether it is satisfied, to take into account the nature of the cause of action or defence, the nature of the subject matter and the gravity of the matters alleged.8 That provision reflects the common law principle in Briginshaw v Briginshaw, where Dixon J explained that reasonable satisfaction is not reached independently of the nature and consequences of the fact to be proved, and that the seriousness of an allegation, its inherent unlikelihood and the gravity of the consequences all bear on whether the court is satisfied.9
In practice this means that a publisher who alleges criminal conduct must produce clear and cogent evidence of it. In Rush v Nationwide News Pty Ltd (No 7), Wigney J observed that the respondents bore the onus of proving substantial truth on the balance of probabilities, that serious matters require clear or cogent proof, and that the gravity of the allegations bore on whether the onus had been discharged.10
The standard is still the civil standard. In Lehrmann, Lee J stressed that the difference between the criminal and civil standards is substantive and can be decisive when the same allegation is examined in each setting, and that a finding of rape on the balance of probabilities is not a finding that excludes every hypothesis consistent with innocence.6 Because the civil standard is lower than the criminal standard, a person acquitted in a criminal court, or never charged, can still be found by a civil court to have done what the publication alleged.
Where the plaintiff has been convicted of an offence by an Australian court, the conviction is conclusive evidence in defamation proceedings that the plaintiff committed it, so the underlying conduct need not be proved again.11
Justifying the imputation, not the words
Because the defence attaches to imputations, the first step for any publisher is to work out what meanings the publication conveys, including by implication, tone, juxtaposition and headline. A publisher that sets out to prove the literal accuracy of each sentence may find that the court holds the article to mean something more serious.
The imputations the publisher must justify are, first, those the plaintiff pleads. Whether a defendant can instead plead and justify its own less serious but not substantially different meaning depends on the jurisdiction: that course is available in Victoria, Queensland and most other states but not in New South Wales. That topic, with the related doctrines of common sting and Polly Peck, is covered in the article on common sting and alternative meanings.
Allegations, rumours and suspicion
A publisher that reports an allegation made by somebody else does not establish truth by proving that the allegation was made. If the publication conveys that the plaintiff did the thing alleged, the publisher must prove that the plaintiff did it. This is often called the repetition rule, and the Full Court of the Federal Court confirmed in 2026 that it forms part of Australian law: a publication that repeats an accusation can only be justified by proving the underlying charge, not the fact that it was made.18 Lehrmann illustrates the point: the broadcast reported Ms Higgins’ account, but because the imputation found to be conveyed was that Mr Lehrmann had raped her, the network could only succeed by proving the rape itself.6
Publications often convey something less than guilt. The High Court held in Mirror Newspapers Ltd v Harrison that a report that a person has been arrested and charged does not, to the ordinary reasonable reader, impute guilt; at most it conveys that the police had reasonable cause to suspect or charge.19 In Favell v Queensland Newspapers Pty Ltd the High Court likewise distinguished an assertion of guilt from an imputation of reasonable suspicion, while warning that loose talk about suspicion can easily convey that the suspicion is well founded.20 An imputation that there were reasonable grounds to suspect the plaintiff is a lesser imputation than guilt, and an imputation that there were grounds to investigate is lesser again; each must be justified on its own terms. To justify an imputation of reasonable suspicion the publisher must prove primary facts that objectively gave rise to reasonable grounds for suspicion, not that the plaintiff was guilty. It is not enough to prove that others suspected the plaintiff, that an investigation was on foot or that someone made an accusation. The facts relied on will usually concern the plaintiff’s own conduct, although the Full Court has said they need not be confined to direct allegations of conduct and that strong circumstantial evidence may suffice.18 The South Australian courts took the same approach in Sands v Channel Seven Adelaide Pty Ltd, where what police or others believed about the plaintiff was not enough.21 The statutory public interest and qualified privilege defences likewise direct attention to whether a publication distinguishes between suspicions, allegations and proven facts.12
The words used to describe an allegation therefore matter, because the meaning conveyed determines what must later be proved. A qualifier such as “allegedly” does not automatically reduce a publication to a report of suspicion. The Full Court has held, for example, that a broadcast using that word still conveyed, read as a whole, that the plaintiffs had done what was alleged.22
Evidence
A justification defence is won or lost on evidence. The publisher must be able to call witnesses with direct knowledge of the facts, or tender documents that establish them. Confidential sources who will not give evidence are of little use at trial. Evidence gathered after publication can be relied on, since the question is whether the imputation is true, not whether the publisher knew it.
Particulars of truth must be pleaded, so that the plaintiff knows what facts the defendant says make the imputation true. Courts can strike out particulars incapable of proving the imputation, and a defendant is generally held to the case it pleads.
When justification fails, or succeeds only in part
A failed truth defence commonly increases damages, through an award of aggravated damages, because the person defamed has had to endure not only the publication but a public trial in which the defendant maintained the truth of the allegation. In Rush, Wigney J found that the plaintiff’s hurt was aggravated by the way the respondents conducted their defence, and awarded aggravated damages.10 The New South Wales Judicial Commission’s bench book describes an unsuccessful justification plea as the most common basis on which the conduct of the litigation is said to aggravate damages.13 Rush was decided before the 2021 reforms, under which aggravated damages are assessed separately from the capped sum for damages for non economic loss.
Proof of part of the truth is not wasted. Where a defendant proves that some but not all of the plaintiff’s imputations are substantially true, the plaintiff recovers damages only for the imputations not proved, and evidence properly before the court on the truth defence can be taken into account in assessing those damages even though the defence failed.14 The New South Wales Court of Appeal has described this as partial justification and listed it among the courses open to a defendant, alongside justification of the pleaded imputations, justification of nuance imputations and contextual truth.15
Where the proven imputations are serious enough, the defendant may do better than mitigation. Under s 26 as amended in 2021, a defendant can rely on the substantial truth of some imputations, including imputations the plaintiff itself pleaded. That defeats the whole claim if the unproven imputations do no further harm to the plaintiff’s reputation. That is the subject of the article on contextual truth.
Three recent examples
Lehrmann v Network Ten Pty Ltd. Network Ten and Lisa Wilkinson defended a claim over a television broadcast on the basis that the imputation of rape was substantially true. After a lengthy trial Lee J found, on the balance of probabilities, that the applicant had raped Ms Higgins and that the defence was made out.6 The Full Court dismissed the appeal in December 2025, rejecting the challenge to the primary judge’s approach to the standard of proof, and the High Court refused special leave to appeal in April 2026.7
Roberts-Smith v Fairfax Media Publications Pty Ltd (No 41). The newspapers defended articles alleging war crimes and other misconduct by pleading justification and contextual truth. Besanko J set out the principles for s 25, including that the defendant carries the onus and that the Briginshaw principles apply, found the most serious imputations substantially true, and dismissed the proceedings.16 The Full Court dismissed the appeal in May 2025, finding that the primary judge had correctly identified and applied the principles, paid close attention to the standard of proof and reached correct conclusions on substantial truth; the High Court refused special leave in September 2025.17
Rush v Nationwide News Pty Ltd (No 7). The Daily Telegraph defended articles about Geoffrey Rush’s conduct during a theatre production by pleading truth. Wigney J was not satisfied that the respondents had proved the substantial truth of any of the imputations, entered judgment for Mr Rush and awarded $850,000 in damages for non economic loss including aggravated damages, with economic loss assessed separately.10
In each case the publisher’s belief in the story was irrelevant; what counted was whether admissible evidence proved the sting.
Differences between jurisdictions
The substantive text of the justification defence is uniform across all jurisdictions, including Western Australia’s unreformed Act, although the section numbers differ as noted above.3 The standard of proof provision in s 140 of the Evidence Act applies in the Federal Court and in the jurisdictions that have adopted the uniform evidence legislation; elsewhere the Briginshaw principle applies at common law to the same effect.9
The interaction between truth and the other parts of the Act does differ. Outside Western Australia the plaintiff must also prove serious harm, and the 2021 amendments to contextual truth give a defendant who can prove some but not all imputations a stronger fallback than it has in Western Australia, where the original s 26 still applies.
Getting advice
Whether a truth defence is viable depends on the imputations the publication is likely to convey, the evidence available to prove them, and the seriousness of what is alleged. For a publisher, the assessment should be made before a concerns notice is answered, because a truth defence that is abandoned or fails can cost far more than an early correction. For a person defamed, the publisher’s likely ability to prove truth is the first question in deciding whether to proceed.
About this article
This article is general information about Australian law as at the review date shown above. It is not legal advice and does not take account of any particular situation. Defamation law differs between states and territories and changes over time. Anyone considering making or defending a claim should obtain advice on their own circumstances before acting.