Australian Strategic Policy Institute national security director Michael Shoebridge told a parliamentary inquiry on Thursday the briefings could cover foreign interference, counter-terrorism and military deployments.

The inquiry is reviewing the impact of police and intelligence powers on press freedom, with Mr Shoebridge saying a healthy disclosure culture would stop outside forces distorting the debate on intelligence matters in Australia.

He said he often heard officials saying journalists couldn't report properly on intelligence matters because they knew little history or context.

"And I think, 'Why is that?'," Mr Shoebridge said.

Mr Shoebridge said the debates around Australia's defamation laws and national security were "parallel" because of the inability to call out perpetrators of foreign interference.

He also criticised the government's "country-agnostic" approach to name nation's behind espionage attacks, saying it didn't pass the pub test.

"The scale and nature of particular foreign interference, notably from the Chinese state, far outweighs interference from other countries," Mr Shoebridge said.

Australian National Security College's Professor Rory Medcalf told the inquiry a free press with investigative powers and courage was a "magic weapon for democracies".

He said the nation's defamation laws were also a "fundamental problem".

"In some ways it's at least as much a threat to the press freedoms we're talking about in this country for national security purposes," Professor Medcalf said.

He said the "caution" media organisations were taking to name political donors linked to the Chinese Communist Party was as an example of this.

Professor Medcalf said he wished the Department of Home Affairs had been "more nuanced" in the debate, with its testimony so far to the committee not grasping the "interplay" between the national interest and the public freedom.

His colleague from the college, Jacinta Carroll, also warned the debate had become oversimplified, damaging Australia's global reputation.

Katherine Mansted, also from the college, said legitimate stories were "falling by the wayside" because journalists felt too intimidated to tell them.

"The chilling effect is possibly one of the biggest concerns here," Ms Mansted said.

She said when the New York Times recently dubbed Australia as one of the "most secretive democracies" it could be used to challenge Australia's credibility as a liberal democracy.

Australian Associated Press