Lawyers for the co-chair of News Corp and chief executive of Fox Corporation have argued in the Federal Court that a new public interest defence isn’t applicable for the online publisher.

“The new dawn promised to the media by reason of this defence is not going to happen,” Sue Chrysanthou SC said on Monday, as both parties try to strike out parts of the case against them.

Rather than the topic of Crikey’s article, a reasonable belief needed to be shown that the defamatory matter at the time of publication was in the public interest, she argued.

Murdoch is suing Crikey over a June 29 opinion piece by political editor Bernard Keane, that was taken down and then posted back online on August 15.

It related to US House of Representative hearings into former president Donald Trump and the Capitol riots in Washington, DC, on January 6, 2021.

Murdoch alleges it contained defamatory meanings including a false claim he entered an illegal criminal conspiracy with Trump to overturn the US 2020 presidential election and incite a mob with murderous intent to march on the Capitol.

The article was titled “Trump is a confirmed unhinged traitor. And Murdoch is his unindicted co-conspirator”.

Defence barrister Michael Hodge KC submitted that a trial is the correct place to test a new defence that had not been subject to judicial determination in Australia.

The way the Murdoch family was invoked in the Crikey article was as controllers of a global media conglomerate that had backed Trump and the lies he spread about the US election being stolen by mass voter fraud, Hodge said.

Keane’s article had associated the Murdochs with the views expressed by a “slew of poisonous Fox News commentators”.

“We would say, obviously relevant to the question of whether that kind of publication is in the public interest, is whether or not the Murdochs have disassociated themselves from those views,” Hodge said.

“If it was the case that Lachlan Murdoch had said ‘I do not believe any of these things, it is not true that the election has been stolen’ … that would seem to be a fact directly relevant to the question of whether or not my client’s publication is in the public interest.

“Conversely, the fact that we say he’s never done that is also in our submission relevant to whether the publication is in the public interest.”

But Chrysanthou said there was no matter of public interest that connected her client to evidence from the US committee hearings.

The only co-conspirators identified in the article “are persons with my client’s surname” and Fox News commentators.

In the final paragraph Keane “out of nowhere” compared her client with Richard Nixon, an unindicted co-conspirator in the Watergate controversy.

The article was about a criminal who had committed an indictable offence and got away with it, Chrysanthou argued.

Murdoch is also claiming Crikey’s publisher Private Media, Keane and editor-in-chief Peter Fray were motivated by malice, predominantly acting to harm Mr Murdoch.

Private Media has applied to have that claim struck out.

Justice Michael Wigney reserved his decision on the pre-trial applications. A nine-day trial is due to start on March 27.

-AAP