Former prime minister Malcolm Fraser and former chief justice of the Family Court Alastair Nicholson are among Australians calling on the Federal Government to protect the human rights of WikiLeaks founder Julian Assange.

The pair are among 72 signatories to an open letter demanding Foreign Minister Kevin Rudd and new Attorney-General Nicola Roxon seek assurances from the Swedish and US governments that they will treat Mr Assange according to international standards of due process.

Crikey journalist Bernard Keane co-ordinated the letter.

He says the signatories fear that if Mr Assange is placed in custody in Sweden, where he is accused of sexual assault, the US will extradite and prosecute him over what Keane says is "legitimate journalism".

"Concerns about the treatment of Julian Assange go beyond whatever people may think about WikiLeaks," Keane said.

"We've seen before the circumstances in which an Australian Government fails to do the right thing by an Australian citizien who for whatever reason the Americans have decided they have a problem with.

"We just don't want to go back to the sorts of circumstances we saw with David Hicks where there was a widespread concern that justice was just not being seen to be done."