A Federal Court judge has criticised the ABC and Fairfax for attempting to use comments made by a federal MP as proof allegations of bribery against Chau Chak Wing were true.

The Chinese-Australian businessman and political donor is suing the two media organisations, as well as journalist Nick McKenzie, for defamation over a Four Corners program and accompanying online story published on June 5, 2017.

Mr Chau argues that among some of the imputations the story conveyed were that he bribed or was involved in a scheme to bribe the former president of the United Nations General Assembly, John Ashe.

The ABC and Fairfax wish to file a defence relying on, among other things, a May speech by the Federal MP Andrew Hastie in which he used parliamentary privilege to name Mr Chau as a co-conspirator in the Ashe matter.

When that was raised in an interlocutory hearing on Wednesday, Justice Steven Rares said it was "extraordinary" that the media companies were "trying to use that as evidence of truth" and that is was an abuse of parliamentary privilege.

"The fact that Mr Hastie wants to say something doesn't prove anything," he said.

The court heard that a company owned by Mr Chau allegedly paid for Mr Ashe to attend a conference, but Justice Rares said it was a "fantasy" to say that Mr Chau must have known about that.

"He's got billions … I bet he does nothing about organising conferences," he said.

The media companies' barrister Peter Gray SC said the story was about warnings from ASIO to major Australian political parties about Mr Chau.

"Federal Parliament is currently considering amending Australia's national security laws in part because of this applicant," he said.

Mr Gray said that means their defence will rely on inferences, because the story was concerned with "spheres which are notoriously opaque" and actions which seem innocent but have concealed or ulterior motives.

However Justice Rares asked: "Why does the fact the subject is national security or espionage, why is that different from any other case?"

Mr Gray said it was a "circumstantial" case and a "mosaic".

Media needs to back up claims: judge

Mr Chau also argues that the program portrayed him as engaging in espionage on behalf of China and the Chinese Communist Party.

Mr Gray said the "traditional or conventional notion of 'espionage' is not all that word means these days".

He said that the present world of espionage and intelligence is "much more complex and subtle" than "old-fashioned" methods such as eavesdropping, peeping through holes or stealing microfilm like James Bond and now involves the exercise of "soft power".

But Justice Rares challenged that.

"If you had said foreign interference you'd not have a problem … you've said he's a spy," Justice Rares said.

Justice Rares said when the media companies make huge claims they need to be able to justify them and he was not going to give them the benefit of the court's processes of discovery to give them evidence they did not have.

He reserved his decision about whether to accept an amended defence from the media companies and Mr McKenzie.