Australia's prime minister has outlined a roadmap for breaking away from Britain, renewing calls for a republic down under.

In Malcolm Turnbull's first speech on the topic since he took the leadership last year, the staunch republican called for a two-stage voting process, with a plebiscite to determine the election model before a referendum on whether or not Australia should become a republic.

Mr Turnbull said questions about how an Australian head of state would be elected - in a US presidential style election or by parliamentary appointment - had weakened support for a republic during a failed 1999 referendum on the topic. He said his belief in the cause was based on “patriotism, pure and simple”.

“Our head of state should be one of us,” he said. “Our president should be a resident… We have no other motive, no other reason than love of country.”