The editor-in-chief of WikiLeaks is calling on Australian journalists to support calls for the federal government to intervene and help free Julian Assange from a British jail.
Kristinn Hrafnsson, also an investigative journalist from Iceland, said the media should be up in arms about the WikiLeaks founder's detention, which he called a "grave attack on press freedom".
"It's not just about Julian Assange," he told reporters on Tuesday.
"This is probably the worst attack on press freedom in the western world in decades."
Mr Hrafnsson said the Australian government must intervene directly to stop the planned extradition and prosecution of Assange by the United States.
He delivered an address to the National Press Club and appealed directly to politicians at Parliament House and journalists in the federal press gallery.
"A man's life is in the line here," he said.
Swedish prosecutors recently dropped rape allegations against Assange, saying too much time has passed and witness evidence was no longer reliable.
Assange faces espionage charges in the US over the leaking of classified government documents, and including footage of an American helicopter attack on unarmed civilians in Iraq in 2007.
He sought asylum from Ecuador to avoid extradition in 2012, and remained inside the embassy until his citizenship was suspended and he was arrested by British police and jailed earlier this year.
Greens senator Peter Whish-Wilson said Assange was not a criminal - instead he had helped to expose war crimes.
He said the government must take action to free him from London's Belmarsh prison.
"Our prime minister, our foreign minister, our defence minister continually say that they can't interfere in the UK, in a foreign government's judicial process," he said.
"But what they can do is appeal directly to the US government - our supposed, close friend and ally - and lean on them to bring Julian Assange home."
Mr Hrafnsson said Assange's plight had gained support from Australia's Media, Entertainment and Arts Alliance, and was gaining momentum among journalists.
"Yes there has been support among journalists here and I am really grateful, but I hope that we can get more - more is needed," he said.
Australian Associated Press