Honest opinion: when a defamatory statement is protected as comment

Much of what is published about public affairs, businesses, professionals and public figures is opinion: reviews, editorials, commentary, social media reactions and the ordinary expression of views about how someone has performed. The law of defamation has long accepted that opinion of that kind deserves protection even when it is damaging, provided the audience can recognise it as opinion and can see the facts on which it rests. That protection is now found in the statutory defence of honest opinion in s 31 of the Defamation Act 2005, which operates alongside the common law defence of fair comment.

This article explains what a defendant must prove to establish the defence, what “proper material” means after the 2021 amendments, how the defence is defeated, and why the defence fails in practice far more often through a problem with the facts than through any finding about the publisher’s honesty.

What the defendant must prove

Section 31(1) provides a defence if the defendant proves three things: that the matter was an expression of opinion of the defendant rather than a statement of fact, that the opinion related to a matter of public interest, and that the opinion is based on proper material.¹ White J summarised the elements in the same three steps in Dutton v Bazzi. That decision was later reversed on appeal, but only on the separate question of whether the imputation was conveyed, which left the honest opinion analysis untouched.²

The defendant bears the onus on all three. In a jury trial in New South Wales, Victoria, Queensland, Western Australia or Tasmania the jury decides whether the defence is established.³

Opinion, not fact

The first element is usually the battleground. The question is objective: whether the ordinary reasonable recipient of the publication would understand that an opinion was being offered rather than a statement of fact being made.⁴ The publisher’s intention does not matter. In Channel Seven Adelaide Pty Ltd v Manock the High Court held that comment may only be defended as comment if it is comment on facts stated or sufficiently indicated, and that the words must make reasonably clear that they purport to be comment and not statements of fact.⁴ The facts must be presented to, or already present in, the minds of the audience as things distinct from the opinion, so that the audience can judge for themselves how far the opinion is well founded.⁴

This is why context and framing matter so much. A statement that someone “is a crook” presented as a bare conclusion reads as an assertion of fact. The same statement following a description of what the person did, from which the writer draws that conclusion, is more likely to be understood as opinion. In Manock itself, a television promotion describing “new facts” and “evidence they kept to themselves” was held to consist of statements of fact, not comment, and the defence was struck out.⁴

The question is not whether the defamatory meaning, considered in the abstract, sounds like an opinion. As O’Callaghan J explained in Deeming v Pesutto (No 3), applying s 31 of the Victorian Act, which is in the same terms, the question is whether the published matter, to the extent that it conveys the defamatory imputation found by the court, is an expression of opinion.⁵ A defendant must address the imputation the court finds was actually conveyed. In that case the honest opinion defence failed at the threshold for four of the five publications. It had been directed to different, milder imputations than those the court found the publications carried.⁵ The Full Court of the Federal Court made the same point in 2026 in Latham v Greenwich: the defence must identify the expression of opinion relied on, by reference to the imputation found to be conveyed, because the distinction between opinion and fact is what the defence turns on.¹² In Thurston v Fox Sports Australia Pty Limited, decided a few weeks later, the Full Court upheld the broadcaster’s defence under s 31(2) for live sports commentary by its commentators describing spectators’ behaviour as a disgrace and calling for a life ban, holding that outraged, evaluative remarks of that kind would be understood by viewers as the commentators’ own judgments rather than statements of fact.¹³

Public interest

The opinion must relate to a matter of public interest. This is a broad concept. The conduct of public figures, the performance of businesses that offer goods and services to the public, the quality of professional work, published books and performances, and matters of public debate all qualify. This element is rarely in dispute and is often admitted.⁵

Proper material

The third element is the one that most often decides the case. Section 31(5) now provides that an opinion is based on proper material if two conditions are met.⁶

First, the material on which the opinion is based must be set out in specific or general terms in the published matter, or be notorious, or be accessible from a reference, link or other access point included in the matter, or be otherwise apparent from the context in which the matter is published.⁶ The Act gives a hyperlink as an example of an access point.⁶ The last two limbs were added by the 2021 amendments and reflect the way opinion is now published online, where the writer reacts to a linked article or a shared post rather than restating its contents.

Second, the material must be substantially true, or have been published on an occasion of absolute or qualified privilege, or have been published on an occasion that attracted the protection of the honest opinion defence itself or the public documents or fair report defences.⁶ In most cases this means the defendant must prove that the facts on which the opinion rests are true. A review that says a restaurant served cold food and that the reviewer would not return is protected only if the food was in fact cold.

Section 31(6) gives some latitude: an opinion does not cease to be based on proper material only because some of the material is not proper material, if the opinion might reasonably be based on the material that is.⁶ A commentator who errs on a peripheral fact does not necessarily lose the defence, provided the opinion could reasonably rest on the facts that were right.

The courts have also required a rational connection between the proper material and the opinion. In Dutton v Bazzi, White J accepted that there must be some rational connection between the material relied on and the opinion expressed, and found that statements by the plaintiff about an unrelated subject could not rationally support the opinion that he “excuses rape”; a shared subject matter was not enough.² The defence failed for that reason, not because of any finding about the defendant’s sincerity, although the judge indicated he would have found against the defendant on honesty had it been necessary.² The Full Court later allowed Mr Bazzi’s appeal on the ground that the tweet did not convey the imputation at all, so the honest opinion findings did not need to be revisited; the trial judge’s analysis of the defence has nonetheless continued to be cited.² In Latham v Greenwich the Full Court confirmed that the defence fails where the facts on which the opinion purports to rest are not proved to be substantially true, however sincerely the opinion was held.¹²

Three versions of the defence

Section 31 contains three parallel defences, and the correct one must be pleaded.¹

Subsection (1) applies where the opinion is the defendant’s own. Subsection (2) applies where the opinion is that of an employee or agent of the defendant, which is the usual position for a media company publishing a columnist or critic. Subsection (3) applies where the opinion is that of a commentator, meaning a person other than the defendant or its employee or agent, which covers a publisher of a reader’s letter, a platform or business displaying a customer’s review, or anyone who republishes another person’s opinion.¹

The elements are the same in each case. The difference lies in how the defence is defeated.

How the defence is defeated

Section 31(4) provides that a defence established under the section is defeated “if, and only if” the plaintiff proves one of three things.⁷ Where the opinion is the defendant’s own, the plaintiff must prove that it was not honestly held by the defendant at the time of publication. Where it is the opinion of an employee or agent, the plaintiff must prove that the defendant did not believe it was honestly held by the employee or agent. Where it is the opinion of a commentator, the plaintiff must prove that the defendant had reasonable grounds to believe it was not honestly held by the commentator.⁷

The onus here shifts to the plaintiff, and the test is a subjective one about honesty. The statute does not ask whether the opinion was fair, reasonable, balanced or correct. As O’Callaghan J put it in Deeming v Pesutto (No 3), adopting the words of White J in Dutton v Bazzi, the opinion must be capable of being rationally based on the proper material, but the ordinary reasonable reader need not reasonably reach the same opinion as the commentator. An opinion may be extreme or even insulting and still be one that the defence protects.⁵ In that case the judge indicated that, had it been necessary to decide, he would not have found that the opinion was dishonestly held. The defence failed anyway because the material relied on was not proper material, since central factual claims in it were found to be untrue.⁵

Malice in the common law sense is not the test under s 31(4). What matters is whether the opinion was honestly held, and a plaintiff who wishes to defeat the defence must plead and prove that it was not. Because the question is one of the defendant’s actual state of mind, evidence of what the defendant knew and had read before publishing, and of any inconsistency between the published opinion and the defendant’s private statements, is usually central.

Relationship with fair comment at common law

The statutory defence is additional to the common law defence of fair comment, which is preserved by s 24 of the Act.⁸ The two defences are commonly pleaded together and generally succeed or fail as one. In O’Brien v Australian Broadcasting Corporation the New South Wales Court of Appeal dealt with the fair comment defence first, holding that the facts on which the opinion was based were sufficiently stated in the article and were true, and then disposed of the challenge to the honest opinion defence on the same reasoning.⁹

There are differences in detail. At common law the comment must be one that a fair minded person could honestly hold on the facts, and the defence is defeated by malice; under s 31 the structure is the three statutory elements and the honesty test in s 31(4). The common law also uses the language of comment rather than opinion, although the underlying requirement that the audience be able to distinguish the comment from the facts is the same.⁴ In practice a defendant who cannot establish the statutory defence rarely succeeds on fair comment.

Practical points

For a publisher, the defence is strongest when the piece sets out or links to the facts, draws conclusions in language that reads as evaluation, and keeps the facts accurate. The 2021 amendments make it easier to rely on linked or contextual material, but they do not relieve the publisher of proving that the material is substantially true. Where the material comes from a privileged source, such as a court judgment or a parliamentary report, the second limb of s 31(5)(b), which covers material published on a privileged occasion, may remove the need to prove truth.

For a plaintiff, the first questions are whether the publication really reads as opinion once the imputation is identified, whether the facts it relies on are true, and whether there is a rational connection between those facts and the opinion. Only if the defendant clears those hurdles does the plaintiff need to confront the honesty question in s 31(4), which is a demanding one.

For both sides, the defence must be pleaded with care. The defendant must identify which subsection is relied on, the opinion said to be expressed, and the material said to be proper material, and the plaintiff who alleges dishonesty must plead it in reply with particulars.

Differences between jurisdictions

The honest opinion defence is in s 31 of the Defamation Act 2005 in New South Wales, Victoria, Queensland and Tasmania, s 29 of the South Australian Act, s 139B of the Civil Law (Wrongs) Act 2002 in the Australian Capital Territory and s 28 of the Defamation Act 2006 in the Northern Territory.¹⁰ The amended proper material test applies in all of those jurisdictions, the Northern Territory having adopted it from 11 August 2025.

Western Australia has not enacted the 2021 amendments. Its s 31(5) retains the original formulation, under which an opinion is based on proper material if the material is substantially true, privileged or protected by the comment, public document or fair report defences, without the express limbs about material that is notorious, accessible by a link or apparent from context.¹¹ The common law position stated in Manock, that the facts may be stated, referred to or notorious, continues to inform how that provision is read.⁴

The honesty test in s 31(4), and the three versions of the defence, are the same in every jurisdiction including Western Australia.¹¹

Getting advice

Whether a publication is opinion or fact, and whether the facts behind it can be proved, should be assessed early and objectively. A publisher who is about to publish a critical piece, or who has received a concerns notice about one, and a person who believes an opinion piece has crossed into false assertions of fact, will each want advice on how the elements of s 31 apply before positions harden.