Malcolm Turnbull has decried the powerful role News Corp plays in Australian politics, saying the media organisation must be held to account.
The former prime minister, who was ousted from the country's top job and more recently as a climate tsar in NSW, has given evidence to a media diversity inquiry on Monday.
"The most powerful political actor in Australia is not the Liberal Party or the National Party or the Labor Party, it is News Corporation," he said.
"And it is utterly unaccountable. It is controlled by an American family and their interests are no longer, if they ever were, coextensive with our own."
Mr Turnbull says he faced a ferocious campaign from News Corp after he was recently named as head of a climate advisory board for the NSW government.
The state government "crumbled" to that but then said it was not because of the media organisation, the former Liberal leader said.
"This is like somebody who is taken down to the police station, beaten over the head until they finally sign a fake confession, the last line of which says: 'I confirm that I did so of my own free will.'"
Mr Turnbull is concerned about the trend of narrowcasting in the news media, where information is being targeted for a niche audience.
"There is now a market for crazy," he said.
"If you doubt the significance of this, just reflect on the damage that Murdoch's publications and outlets particular in the United States have done to democracy there."
The one-time journalist pointed to the storming of the United States Capitol in early January, propelled by reports from Rupert Murdoch owned media organisations the election had been stolen from former president Donald Trump, who had lost.
Mr Turnbull also criticised the organisation for promoting animosity towards Muslims and preventing effective action on climate change.
"At a huge cost to all of us."
Mr Turnbull blames News Corp and radio shock jocks for helping to fuel his demise.
One of Mr Turnbull's predecessors, Kevin Rudd, has already called out the "Fox News-isation" of the Australian media that he says is breeding climate-change denialism and encouraging far-right political extremism.
Mr Rudd gave evidence last month that he was "fearful" of News Corp until he left parliament in 2013.
"The truth in this building is that everyone's frightened of Murdoch," he said.
Mr Turnbull on Monday said it was easier to speak out against the media behemoth after leaving politics.
"Being as candid as I have been today is something that you would do at your peril if you were prime minister or a minister or you wanted to keep staying in parliament, because the retribution would be very intense," he said.
"Even if you were prepared to take the heat, your colleagues definitely wouldn't."
