How far does the public interest defence reach? Lessons from Al Muderis v Nine Network

When does a publisher’s reasonable belief that a story serves the public interest shield them from defamation liability, even where not every published allegation can be proven true?

That question lies at the heart of Al Muderis v Nine Network Australia Pty Ltd [2025] FCA 909 (Al Muderis), the first case in which the statutory public interest defence has succeeded at trial. The decision is significant because it transforms section 29A of the Defamation Act 2005 (NSW) (Defamation Act) from a largely aspirational reform into a defence capable of succeeding in practice. It does so in the context of a substantial and heavily contested proceeding: a 65-day hearing, involving 75 pleaded imputations, evidence from 29 patients and legal costs accruing at reportedly around $19 million.

Section 29A was introduced as part of the 2021 reforms to Australian defamation law to protect responsible publication on matters of public importance which are otherwise defamatory. The defence turns on: first, whether the defamatory matter concerns an issue of public interest; and second, whether, at the time of publication, the publisher reasonably believed publication of the matter was in the public interest.

Behind the headlines: the Al Muderis proceeding

Dr Munjed Al Muderis is one of Australia's most prominent orthopaedic surgeons, internationally recognised for his work in osseointegration surgery. In September 2022, following a joint investigation spanning several months, Nine Network, The Age and The Sydney Morning Herald published reports across television, print and online, alleging improper sales tactics, inadequate disclosure of surgical risks, deficiencies in aftercare and an undue focus on commercial outcomes over patient welfare.

Nine relied on several defences, including contextual truth and public interest. Justice Abraham ultimately found those defences were established in relation to the imputations that were conveyed.

The decision provides the most thorough judicial examination of section 29A to date and, importantly, the first successful application of the defence. The Court was required to confront one of the most difficult questions raised by section 29A: what is the relationship between public interest and truth?

Public interest is not truth

The Defamation Act does not define ‘public interest’. Broadly speaking, a matter qualifies where it affects people beyond those immediately involved and is capable of legitimately engaging public attention or concern, extending beyond politics and government to public welfare, professional conduct, the administration of justice and the provision of goods and services. Critically, public interest and public fascination are not the same thing. A story may attract clicks, dominate headlines and become the subject of animated dinner-party debate while still failing to serve the public interest. Equally, widespread attention does not, of itself, mean a publication serves a public interest. Courts have long distinguished between matters that genuinely affect or concern the public and those that simply trade in salacious or scandalous gossip. There is no sliding scale by which the strength of public interest in a topic widens the permissible margin for error. Section 29A still requires the publisher's belief to be objectively reasonable. Defamation law has traditionally looked backwards: was the allegation true? Section 29A asks a different question: was the decision to publish reasonable when it was made? That shift places the spotlight on process as much as outcome.

Section 29A proceeds on the basis that publication decisions cannot always wait for a flawless factual record. Responsible publication is not the same thing as perfect publication. The question is not whether every aspect of the publication was ultimately shown to be correct, but whether the publisher's belief that publication was in the public interest was objectively reasonable at the time.

The distinction was foreshadowed in Russell v Australian Broadcasting Corporation (No 3) [2023] FCA 1223 (Russell). In this case, although the Court accepted the publisher genuinely believed that publication concerning allegations linking an ADF officer to a criminal investigation into the execution of an unarmed Afghan prisoner served the public interest, the defence failed because that belief was held not to be objectively reasonable.

Al Muderis provided precisely the test case that Russell did not. Questions of patient safety, informed consent, medical regulation and public confidence in healthcare systems plainly engaged matters of public interest, and, unlike Russell, Justice Abraham found the respondents’ belief that publication served that interest was objectively reasonable. Where Russell demonstrated the limits of section 29A, Al Muderis provides the first substantial guidance on the circumstances in which it may succeed.

The anatomy of a successful public interest defence

Justice Abraham’s analysis makes clear the defence rewards thoroughness: breadth of sources, corroboration, assessment of credibility and rigorous verification. The journalists had spoken with approximately 76 sources across diverse backgrounds, reviewed extensive documentary material and made substantial efforts to verify information before publication, through source testing, corroboration and careful scrutiny of the material gathered.

The judgment also illustrates that not all publicity is in the public interest. Justice Abraham placed significant weight on the fact that the publications engaged questions of patient safety, informed consent, public accountability and regulatory oversight – matters that objectively sit squarely within the concept of public interest.

Importantly, the reasoning suggests that flaws, omissions or imperfections in an investigation will not necessarily defeat the defence, and that may be the judgment’s most significant feature. Sources disagree, evidence emerges over time, and investigations are rarely without imperfection. For investigative reporting on matters of public significance, that is unavoidable. At its core, Al Muderis recognises that responsible publication is not the same thing as perfect publication.

Two further features assumed particular significance. The respondents made a genuine, honest and reasonable attempt to put the allegations to Dr Al Muderis before publication and reflected the substance of his responses in the articles. They also distinguished carefully between suspicions, allegations and proven facts, declining to report on unsupported allegations. Together, these features illustrate both the conduct that will support the defence and the standards against which any publisher’s decision-making will be measured.

Which publisher’s belief matters?

A further question concerned whose belief is relevant where a corporate publisher relies on section 29A. Dr Al Muderis contended that, without evidence from those ultimately responsible for the decision to publish, the defence must fail. Justice Abraham rejected that submission, as had Justice Lee in Russell, finding that the relevant inquiry focuses on those substantially responsible for the publication, in this case the journalists themselves.

Where a news organisation relies on section 29A, the relevant belief is that of the journalists and others substantially responsible for the publication – not necessarily the most senior executive in the chain. The question of whose belief counts may have broader significance wherever publication decisions involve multiple contributors.

The battle before the Full Court

Dr Al Muderis has appealed to the Full Court, which must now resolve questions that go to the heart of how section 29A operates in practice:

• Whose belief is the relevant belief? Publication decisions rarely rest with a single individual in large media organisations – journalists, editors and legal advisers may each contribute to a final published version. When a media organisation relies on section 29A, is the relevant belief that of the journalist who conducted the investigation, the editor who approved it, or the executive who authorised publication? A finding that only the most senior decision-maker’s belief counts could make it significantly harder for large newsrooms, where responsibility is distributed, to satisfy the defence.
   
• When do imperfections undermine reasonableness? The Full Court must consider how errors, omissions and factual inaccuracies bear on whether a publisher’s belief was objectively reasonable. If minor inaccuracies are treated as fatal to the defence, the practical effect may be to impose a standard of pre-publication verification that is unrealistic in the context of time-sensitive investigative reporting.
   
• How does the objective reasonableness standard accommodate editorial judgment? Section 29A requires courts to make allowances for editorial judgment, but the Full Court must define where scrutiny of a journalist’s choices crosses into impermissible second-guessing of reasonable professional judgment. How broadly that latitude is drawn will determine whether the defence provides meaningful protection for editorial discretion or functions primarily as an incentive to conform to judicial expectations of journalistic process.
   
• Do conflicts and source protection matter? The appeal will consider whether the lead journalist’s personal connection to an originating source should have been disclosed, as well as challenges to rulings protecting confidential sources and setting aside subpoenas directed at potential sources. These grounds raise a novel intersection between the public interest defence and journalists’ privilege. The Full Court’s treatment may clarify how undisclosed conflicts and source confidentiality obligations interact with the reasonableness assessment under section 29A.

Lessons beyond traditional media

Section 29A is not confined to investigative journalism or traditional media organisations. Justice Abraham emphasised the defence is capable of application across a range of publication contexts, provided the publication concerns a matter of public interest and the publisher holds a reasonable belief that publication serves that interest. Although Al Muderis arose in a media context, the principles it identifies may prove relevant wherever publishers seek to rely on a reasonable belief that publication served the public interest.

What Al Muderis makes clear is the availability of the defence will turn heavily on process. Courts will closely scrutinise the steps taken before publication: how information was verified, how sources were tested for credibility, whether competing accounts were sought and what opportunity was given to affected persons to respond before publication. These are not merely good journalistic habits but the evidential building blocks from which a publisher must construct a case for objective reasonableness, even though section 29A does not require proof of all of them. For organisations that publish on matters of public significance but operate outside traditional editorial frameworks, the judgment is a practical prompt to develop and document rigorous pre-publication processes. In the absence of an established editorial culture, the quality of that process is likely to be the decisive factor in any defence under section 29A.

Considerations for publishers

Al Muderis also provides a roadmap for how publishers can demonstrate responsible publication in practice:

• Conduct and document a thorough investigation. Courts will examine the breadth of sources consulted, the steps taken to corroborate information and the rigour of the verification process. Thorough investigation must also be documented, as a publisher who cannot reconstruct the pre-publication process in evidence may struggle to establish its belief was objectively reasonable.
   
• Seek and accurately reflect the subject’s response before publication. Justice Abraham placed significant weight on the fact that the respondents put the allegations to Dr Al Muderis before publication and reflected the substance of his responses in the published articles. Failure to seek a response, or to reflect it fairly, may be difficult to reconcile with a claim that the publisher genuinely and reasonably believed publication served the public interest.
   
• Document publication decisions as if they will be examined in court – because they may be. The ability to demonstrate, years later in litigation, what information was available at the time of publication, who held it, how competing views were weighed and why publication proceeded may prove decisive. Publishers should maintain contemporaneous records of editorial meetings, legal reviews and the reasoning behind decisions to publish or withhold material.
   
• Identify a concrete public benefit before publishing. Section 29A is not engaged merely because a matter is newsworthy, of general interest or commercially valuable. Publishers should be able to articulate the specific public interest the publication serves. A vague or post-hoc rationalisation is unlikely to satisfy the objective reasonableness standard.
   
• Exercise disciplined judgment about what not to publish. The public interest defence does not protect scandalous or salacious material merely because it accompanies a legitimate public interest story. In Al Muderis, the respondents’ deliberate decision to withhold allegations they considered unsupported was treated as strong evidence of responsible journalism. Restraint, and the ability to demonstrate it, can be as important as the decision to publish.
   
• Distinguish carefully between suspicions, allegations and established facts. Language matters. Presenting unverified allegations as established fact or failing to qualify the evidential basis for serious claims, undermines the objective reasonableness of the publisher’s belief and may expose the publisher to liability that the defence cannot cure.

Whatever the outcome, the appeal will shape the legal framework through which courts assess publication decisions for years to come. If the Full Court upholds the decision, it cements Al Muderis as the leading authority on section 29A. If it reverses, it will add to a growing line of cases in which the defence has not been successfully established, prompting renewed debate about whether the provision is operating in the way the reforms intended.

Even before the appeal is determined, the first instance decision offers a clear lesson: the foundations of a successful public interest defence are laid before publication, not after proceedings commence. The quality of the investigation, the robustness of the decision-making process and the contemporaneous record of those decisions may ultimately prove just as important as the publication itself.