Professor Greste, who spent 400 days behind bars in an Egyptian prison, says Australia should be a regional leader for a free press.

Appearing before a Senate committee on Wednesday, he used Malaysia, Myanmar, Thailand and the Philippines as examples of countries which have recently prosecuted, locked up or expelled journalists.

He also noted the arrest of newspaper owner Jimmy Lai this week in Hong Kong under a new national security law imposed by Beijing.

"Unless we move decisively to address our own weaknesses over press freedom, we will become an example for the region's autocrats rather than a beacon for its democrats," Professor Greste told the committee.

"For all its flaws we must see a free press as part of our national security architecture rather than something that stands in opposition to it."

Prof Greste, a former foreign correspondent, says the media also has a role to play in rebuilding trust.

He and others from the Alliance for Journalists' Freedom made a raft of recommendations to the inquiry.

They want an exemption from prosecution for journalists over national security offences and beefed up whistleblower protections.

AJF director Chris Flynn doesn't believe Australia's leaders intend to limit press freedom, but highlighted the practical effect of ever-increasing national security laws.

Media representatives banded together through the Australia's Right To Know campaign also fronted the inquiry, telling senators it was time for a federal corruption commission.

Senior Nine reporter Chris Uhlman also told senators the current Freedom of Information system was a "complete joke".

He's been trying to get his hands on a police letter regarding Nationals MP George Christensen's frequent trips to the Philippines.

But Ulhmann has been handballed from agency to agency and told releasing the letter could jeopardise national security.

The inquiry was sparked by two controversial police raids, one on the Canberra home of a News Corp journalist Annika Smethurst and the other on the ABC's Sydney headquarters.

The High Court later struck out the warrant used to raid Smethurst's home and police said charges would not be laid.

News Corp executive Campbell Reid argued for an opportunity to contest warrants before they're issued, saying the High Court battle was evidence of a broken system.

"You don't go to the High Court unless something has gone wrong," he said.

Australian Associated Press