The ads have been taken out by national campaigning organisation calling itself GetUp!
Executive director Brett Solomon said more than 35,000 Australians had signed a letter on the organisation's website, calling on the Australian government to repatriate Mr Hicks.
"With the recent US Supreme Court decision that the process to try Hicks is completely flawed, we now need from our prime minister a timetable as to what he will do to stop Hicks rotting in jail for another four-and-a-half years," Mr Solomon said.
"If the British can get their citizens out of Guantanamo, why can't we?"
Mr Hicks, 30, originally from Adelaide, has been held by US authorities at Guantanamo Bay, Cuba, since soon after he was captured with Taliban forces in Afghanistan in late 2001.
He has pleaded not guilty to attempted murder, aiding the enemy and conspiracy at a military commission hearing in August 2004 but has not faced trial.