Australian media outlets are liable for what users post on their corporate Facebook pages, according to a court ruling.

The High Court ruled on Wednesday that Australia's largest news publishers, including Rupert Murdoch's the Australian, are responsible for comments made by readers on their corporate Facebook pages. Dylan Voller, a young man who had been the subject of several news reports about youth detention, had filed an appeal against a previous ruling that found in his favor in a defamation suit.

After the ruling, Voller's lawyers, O'Brien Criminal and Civil Solicitors, said in a statement, "This is a common-sense decision that accords with longstanding law on the issue of publication."

After stories about him were posted on the news organizations' Facebook pages, a number of third-party Facebook users made defamatory comments, according to Voller, who claimed that the news organizations were liable as publishers.

Voller sued the publishers, including Fairfax Media, the publisher of the Sydney Morning Herald newspaper, which is owned by Nine, and others.

Following the court's decision in Voller's favor, the media outlets filed an appeal, claiming that they ran a Facebook page where third parties posted their own content.

The appeal was dismissed by the High Court, and the organizations were ordered to pay costs.

"The (media companies') actions in facilitating, encouraging, and thus assisting the posting of comments by third-party Facebook users made them publishers of those comments," Justice Rothman concluded.

Facebook did not allow page moderators to turn off comments on posts at the time the comments were published, but that has since changed.

The case will now be heard in the Supreme Court of New South Wales to see if any of the comments were defamatory to Voller.

Nine was "disappointed with the outcome... as it will have ramifications for what we can post on social media in the future," according to a spokesperson.

The court decision, according to Michael Miller, executive chairman of News Corp Australia, is significant for anyone who maintains a public social media page.

"Even if they are unaware of the comments made by others on that page, they can be held liable," he said.