The Prime Minister, Julia Gillard, has thrown her support behind a republic, but only when Queen Elizabeth is no longer the monarch.

Ms Gillard, who is pitted against the fierce monarchist, Tony Abbott, in a race for the prime ministership said the most appropriate time to move towards a new model of government would be after the Queen's current reign.

"I am obviously a republican," Ms Gillard said.

"I believe that this nation should be a republic. I also believe that this nation has got a deep affection for Queen Elizabeth.