Speaking at Australian Republican Movement’s (ARM) 25th anniversary dinner overnight, Turnbull said Australians were unlikely to back the republican push while the Queen was still ruling.
He, however, did not rule out a vote in the near future, Xinhua news reported.
Turnbull headed the republican movement from 1993 to 1999, including the group’s failed vote in 1999.
“I do not believe Australia would welcome, let alone support, another public referendum during her (Queen Elizabeth II’s) reign,” Turnbull said on Saturday night.
He said any push for Australia to formally become a republic would be a “slow burn,” which must be thought out and embraced by all Australians regardless of how they vote.
“We would need to have an advisory plebiscite which would offer a choice between two republican models, presumably direct election and parliamentary appointment,” he said.
Turnbull’s comments came a day after the current head of the ARM, Peter FitzSimons, said for the first time, there was majority support in the parliament for an Australian republic.
Following Turnbull’s cautious approach to the subject on Saturday night, FitzSimons acknowledged the challenge ahead for the group.
“He’s the prime minister – he’s experienced in this field and he’s saying make no mistake you have a long hill to climb,” FitzSimons said.
“The point that I’m about to make in return is … we are climbing that hill, we’ve got extraordinary enthusiasm.”
The plan has also received backing from the nation’s opposition leader, Bill Shorten.
Shorten posted on social media: “My offer still stands – let’s work together to deliver an Australian head of state.”
In 1999, Australia narrowly voted against leaving the British monarchy to become a republic.