Media chiefs have raised concerns about a "creeping secrecy that shrouds Canberra" as they demand changes to laws criminalising journalism.
A dozen senior executives from Australia's major media organisations are appearing before federal parliament's powerful intelligence and security committee in Sydney on Tuesday.
They are demanding changes to national security laws that inhibit journalism.
News Corp executive chairman Michael Miller spoke of politicians stamping documents "secret" and hiding behind laws that keep Australians in the dark.
"We have many laws that criminalise journalism. They are creating a secret society that most Australians would not recognise as our own," Mr Miller told the committee.
"We may not be living in a police state, but we are living in a state of secrecy.
"The package of law changes that we are seeking will put a stop to the creeping secrecy that shrouds Canberra."
ABC managing director David Anderson called for stronger protections for whistleblowers, while Nine chief executive Hugh Marks described recent police raids as "a real wake up call".
"We're here to talk about laws - old and new laws - that are being used to unreasonably and unnecessarily inhibit the media," Mr Marks told the committee.
"Issues of national security are clearly important, but so is truth."
Mr Marks urged the committee to consider exemptions to various national security laws for legitimate media activity.
"It is true that nobody is above the law, but we need the right laws," he said.
"The current tone being set seeks to restrict, not respect, a free media."
Their joint appearance comes after Australian Federal Police raids on the Canberra home of a News Corp journalist and the Sydney office of the ABC over separate investigations into government leaks.
The AFP raids were widely condemned as heavy-handed and for having a chilling effect on reporting.
Senior figures from the ABC will also appear before the committee, along with various human rights and legal advocates.
On Wednesday, the committee will hear from law enforcement and intelligence agencies including the AFP.
Ahead of the public hearings, Labor's Mark Dreyfus argued the government remained resistant to improving press freedoms.
"We don't seem to have, even now, any acceptance by the government that there actually needs to be some change," Mr Dreyfus told Sky News.
Ahead of the public hearings, Home Affairs Minister Peter Dutton gave new directions to the AFP on investigations into journalists and media organisations.
He expects AFP officers to "exhaust alternative investigative actions" and seek the voluntary co-operation of journalists and media organisations, before considering further action.
As well, government departments and agencies will need to provide a "harm statement" before referring a leak to the AFP.