Assange's message, videotaped in Britain, was played at a free-speech forum in Melbourne, The Sydney Morning Herald reported. The newspaper also posted the video on its Web site.
Assange urged Prime Minister Julia Gillard to get him back to Australia before Monday, when he is scheduled to appear in a British court for a hearing on his extradition to Sweden. At the same time, he accused the prime minister of "talking about human rights while trying to downplay attacks on journalists."
Gillard suggested Assange was a lawbreaker after WikiLeaks began publishing thousands of leaked U.S. diplomatic cables. Australian authorities later said there was no evidence he had broken that country's laws.
U.S. authorities are apparently trying to determine if Assange can be prosecuted there. In Sweden, he is charged with sex crimes.
"She should be contacting the U.S. Embassy and demanding that it back off," Assange said.