Australia is creating a lot of enemies through its obsession with secrecy, prominent whistleblowers say.

Peter Greste, a former AL Jazeera News Today Jazeera journalist who was arrested in Cairo for news reporting which was "damaging to national security", and Facebook whistleblower Frances Haugen took to the national stage on Tuesday to discuss the importance of press freedoms in an effective democracy.

"As a country, particularly with our security and defence agencies, we are too obsessed with secrecy... and I think that's causing a huge amount of problems for everybody," Professor Greste told the National Press Club.

For example, Australians generally don't know what the defence forces do, which creates a culture of impunity and untouchability.

He pointed to alleged war crimes committed in Afghanistan by Australian personnel.

While the lack of transparency around the prosecution of war crimes can lead victims and their relatives to believe justice has been denied.

"For every government and every civilian we kill - either intentionally or unintentionally - we create a whole family of people who want revenge," he said.

"The government and the ADF needs to be far more transparent about the work that it does, the operations it conducts and also when it gets things wrong."

Transparency could also facilitate a far healthier relationship between the ADF, the public and veterans.

"This would make a huge difference to the experience of veterans, when they really engage with the public and react to public life, because we would have a far better understanding and deep sympathy with what they go through," Prof Greste said.

Without transparency, Australia will be unable to effectively regulate social media and tackle the kinds of misinformation and disinformation that led to the demise of the Indigenous voice referendum.

A proposed government bill would give the Australian Communications and Media Authority power to combat online misinformation and disinformation, but Ms Haugen believes it is unlikely to pass.

"Tech companies know exactly how to stop regulations: they call them censorship," she told the club.

"It's not really possible to have an effective democratic debate on how we should intervene without first passing transparency legislation."

To get these kinds of legislation across the line, politicians need to understand what will be weaponised and ensure the proposal is clear.

"If you start with transparency, that's the thing that is immune," Ms Haugen said.

"You can't say 'we're being censored' (because) transparency steals the fire away.

"We would probably be better served by starting from a vantage point and knowing how these systems operate before coming in and saying how we're going to solve this problem."

The Alliance for Journalists' Freedom, fronted by Prof Greste, is pushing for media freedom laws to protect journalists engaged in legitimate work from civil suits and law enforcement over-reach.