The serious harm element: the threshold most claims now have to clear

Until 2021, a plaintiff who proved that defamatory matter had been published about them was presumed to have suffered damage, and the burden fell on the defendant to show that the circumstances were so trivial that no harm was likely. The serious harm element reversed that position. In every jurisdiction except Western Australia, the plaintiff must now prove that the publication has caused, or is likely to cause, serious harm to their reputation, and a judge decides the question, usually early. Section references are to the Defamation Act 2005 (NSW) unless otherwise stated.

The text of s 10A

Section 10A(1) provides that it is an element of a cause of action for defamation that the publication of defamatory matter about a person has caused, or is likely to cause, serious harm to the reputation of the person.¹ Where the plaintiff is an excluded corporation, harm to its reputation is not serious harm unless it has caused, or is likely to cause, the corporation serious financial loss.²

Although a jury may still decide other liability questions in some jurisdictions, the judicial officer alone determines whether the serious harm element is established.³ The judge may decide the question at any time before or during the trial, on a party’s application or on the court’s own motion, and may make any orders appropriate to that determination, including dismissing the proceedings if satisfied the element is not established.⁴ If a party applies for a determination before trial, the judge must decide it as soon as practicable before the trial commences unless satisfied that there are special circumstances justifying postponement, having regard to matters such as the cost implications, the court’s resources and the extent to which serious harm is linked to other trial issues.⁵ The judge may also find that serious harm is not established on the pleadings alone, without further evidence, if the pleaded particulars are insufficient.⁶

The provision was modelled on s 1 of the Defamation Act 2013 (UK), and the Supreme Court’s decision in Lachaux v Independent Print Ltd on that section has been influential here. Lord Sumption held that the section raised the threshold of seriousness above the common law tests and required actual harm to be proved by reference to the facts, not presumed from the inherent tendency of the words.⁷ Whether a statement has caused serious harm depends on its actual impact, and whether it is likely to do so depends on its probable future consequences.⁸ Proof may nonetheless be inferential. In Lachaux the inference was drawn from the scale of publication, the gravity of the allegations and the fact that they had come to the attention of people who knew the claimant.⁹

Australian courts adopted that reasoning quickly. In Newman v Whittington, Sackar J held that there is no material difference between s 10A and the UK provision, adopted much of Lord Sumption’s analysis, and concluded that s 10A has the effect of abolishing the common law rule that damage is presumed on publication, so that the plaintiff must prove serious harm as a fact in every case.²⁸ That consequence of the reform applies only to matter published on or after the date s 10A commenced in the relevant jurisdiction. For earlier publications, and in Western Australia, the common law presumption of damage continues to apply. The extrinsic materials show that the provision was introduced to weed out trivial, spurious, frivolous and vexatious claims, and the early determination procedure reflects that purpose.¹⁰

What serious harm means

The NSW Court of Appeal in Rader v Haines distilled propositions from the English authorities. Serious harm is concerned with actual or likely reputational damage, arising from a combination of the inherent tendency of the words and their actual impact on those to whom they were communicated. It is not satisfied by the gravity of the imputation alone, nor by injury to feelings, however great. Relevant factors include the meaning of the words, the extent of publication, the nature of the recipients and their relationship with the plaintiff, and whether they believed the imputations. A grave imputation may not result in serious harm, typically where publication is to a small number of people well acquainted with the plaintiff who are not disposed to believe it.¹¹

Brereton JA in Rader also suggested that “serious” means more than merely substantial though less than grave. Basten AJA cautioned against placing the word on a scale between other imprecise terms, and later decisions have preferred that reservation.¹² The Queensland Court of Appeal in MG v PJ held that “serious” should bear its plain and ordinary meaning, read with the purpose of the provision,¹³ and the Full Federal Court in Latham v Greenwich adopted the same approach, describing the question as calling for an evaluative conclusion on the evidence in the exercise of the court’s own judgment, in which precision will rarely be possible.¹⁴ The High Court refused special leave to appeal from Latham v Greenwich on 8 October 2026.¹⁵

MG v PJ distilled seven principles: the plaintiff must prove serious harm as a fact; it may be established by direct evidence, inference or both, but will never be presumed; the assessment may depend on the inherent tendency of the words, their impact on recipients and the extent of publication, having regard to all the circumstances; it is a qualitative inquiry; reliance on the gravity of the imputation alone will not suffice; mere injury to feelings is not enough; and the evidence must establish that the publication caused or was likely to cause serious harm to the plaintiff’s reputation.¹⁶

How serious harm is proved

Because harm to reputation exists in the minds of others, direct evidence can be hard to obtain. The courts allow for that difficulty but insist on proof. In Latham v Greenwich the Full Court identified circumstances from which an inference of serious harm may be drawn: the gravity of the imputations and their probable impact on recipients; the extent of publication, likely republication and any grapevine effect; whether there was a prompt apology and how widely it was published; the reputation of the publisher, since a reputable publisher presenting researched material may cause more harm; the medium, since a transient publication may cause less harm than one available online indefinitely; the plaintiff’s existing reputation in the relevant sector; the identity of the recipients; and the inherent probabilities. The list is not a checklist and is not exhaustive.¹⁷

In practice, courts look for proof of how many people read or heard the publication and who they were; evidence from recipients about how their view of the plaintiff changed; evidence of consequences such as lost work, exclusion from a group, confrontations and online reactions; and evidence of republication and continuing accessibility. In Latham v Greenwich, the inference of serious harm was supported by findings about the responses to the tweet, including social media posts the trial judge described as hate filled venom, and the fact that the plaintiff retained a good reputation among colleagues did not negate the finding of serious harm.¹⁸ Serious harm does not require that reputation be damaged in every quarter; the impact may be serious without being uniform.¹⁹

Two further points follow from the Full Court’s reasoning. First, serious harm is assessed by reference to the publication of the matter as a whole, not imputation by imputation. The plaintiff does not have to show that each pleaded imputation separately caused serious harm.²⁰ Second, the single meaning found by the court provides a sound basis for inferring the impact of a widely circulated publication, even though real readers will have understood it in different ways.²¹

Cases where serious harm failed

Decisions since 2021 show the kinds of claims the element excludes. Rader v Haines, the source of the propositions set out above, is itself a case in which serious harm was not established. A man sued his estranged wife’s parents over an email sent to his own parents in England accusing him of theft and abuse. The Court of Appeal upheld the dismissal of the claim. The recipients were his parents, who were well disposed towards him and did not believe the allegations, and the imputations, though grave, caused no serious harm to his reputation in their eyes.²²

In Zimmerman v Perkiss, a single Facebook Messenger message about a former employee was sent to her new employer, who gave evidence that it did not affect her view of the plaintiff, and serious harm was not established.²³ In Scott v Bodley (No 2), a negative review on a tradesman’s Google listing and business Facebook page was online only briefly, there was no evidence that anyone had read it, and the claim was dismissed.²⁴ In Selkirk v Wyatt, the Full Federal Court upheld the dismissal, after a separate hearing, of a claim over an online news article about the plaintiff’s criminal case. The article had reached very few people, and the only evidence of harm was the plaintiff’s own assertion that the imputations posed a risk to her future employment, with nothing to connect any loss to the article.²⁵ The Full Court also held that s 10A removes any presumption of good reputation (if one existed at common law) along with the presumption of damage, that a plaintiff may be expected to lead evidence of their existing reputation, and that a defendant who relies on the plaintiff’s prior bad reputation to answer serious harm bears the onus of proving it.²⁶

The Queensland Court of Appeal’s decision in MG v PJ shows the same approach to publications made to officials. Statements by family members to police, repeated in police protection notices, were published only to a small and unknown number of officers who were not called to give evidence. The court held that police officers are expected to act professionally and with detachment, that the inferential reasoning available for mass media publications was not available for so limited a publication, and that serious harm was not established.³⁶

Peros v Nationwide News Pty Ltd (No 3) illustrates a different basis on which a serious harm claim can fail: earlier publicity. The plaintiff sued over a podcast that discussed his possible involvement in a death. Applegarth J found that the episode complained of added little to the harm already done by earlier episodes of the same podcast, which had reported the coroner’s findings, and by earlier publicity, and that serious harm was not proved. Repetition of material that has already been widely published may add little to the harm attributable to the later publication.²⁷

Cases where serious harm was established

Serious harm is not an impossible hurdle. In Martin v Najem, Gibson DCJ held that Instagram videos by one food blogger about another, calling the plaintiff a paedophile and a racist, caused serious harm. The allegations were among the gravest possible, they were published as a call to the defendant’s followers to harm the plaintiff, third parties responded with threats, and the plaintiff’s health, work and movements were affected over six months.²⁹ In Latham v Greenwich, a single tweet about a member of parliament, widely viewed and republished, was found to have caused serious harm notwithstanding the plaintiff’s continuing good reputation among those who knew him.¹⁸

The common thread is evidence of who received the publication, why those recipients mattered and what happened as a result.

Corporations

An excluded corporation, that is, a not for profit body or a corporation with fewer than 10 employees that is not an associated entity of another corporation, must prove that the publication has caused or is likely to cause it serious financial loss.² Loss of goodwill or standing, by itself, is not enough. There must be evidence of actual or probable financial consequences, such as lost contracts or a measurable downturn attributable to the publication. The concerns notice must also set out the financial loss the corporation considers to be serious financial loss.³⁰ Individuals, by contrast, need not prove any financial loss; harm to reputation in a social or professional sense is sufficient if it is serious.

Timing, procedure and costs

Section 10A pushes the serious harm question to the front of a case. A defendant who considers the claim trivial can apply for an early determination, and the court must decide it before trial unless there are special circumstances.⁵ The defendant can also seek dismissal on the pleadings where the particulars of serious harm are inadequate.⁶ Where the question is bound up with issues that require trial evidence, courts have sometimes postponed the determination.

For plaintiffs, serious harm must be pleaded with particulars from the outset and supported by evidence as early as possible. The concerns notice that must precede proceedings has to inform the publisher of the harm the aggrieved person considers to be serious harm to their reputation.³¹ A notice that describes damage only in general terms invites challenge. A plaintiff whose claim is dismissed for want of serious harm will ordinarily pay the defendant’s costs.

Western Australia

Western Australia has not enacted any of the 2020 model amendments. Its Defamation Act 2005 contains no serious harm element, and the plaintiff continues to have the benefit of the common law presumption of damage.³² The defendant may instead rely on the defence of triviality in s 33, which requires the defendant to prove that the circumstances of publication were such that the plaintiff was unlikely to sustain any harm.³³ That defence has been repealed in the reformed jurisdictions. The Northern Territory adopted the serious harm element as s 9A of the Defamation Act 2006 (NT) from 11 August 2025,³⁴ and Tasmania inserted s 10A from 12 November 2021.³⁵ Which law applies to a particular publication depends on the choice of law rules in the Acts.

Getting advice

Serious harm is now the element on which most marginal claims succeed or fail. A plaintiff considering a claim should expect to be asked, before any letter is sent, who saw the publication, what those people did and what evidence can establish it. A publisher who receives a concerns notice should assess early whether the harm alleged can be proved and whether an application under s 10A is likely to dispose of the claim.