The head of the Australian Republican Movement believes there is widespread support for a republic, calling on Prime Minister Malcolm Turnbull to "seize this moment".
"We could actually do this now," Peter FitzSimons told ABC TV on Monday.
It comes after seven out of eight state and territory leaders signed a declaration calling for an Australian head of state.
Only Western Australian Premier Colin Barnett refused to sign the declaration, which says Australia should have an Australian as its head of state.
Australian Republican Movement chair Peter FitzSimons said it was a clear declaration of desired independence by almost all the country's state and territory leaders.
All Australia's political leaders, including Prime Minister Malcolm Turnbull and Opposition Leader Bill Shorten, now supported the move to a republic, he said.
"Never before have the stars of the Southern Cross been so aligned in pointing to the dawn of a new republican age for Australia," Mr FitzSimons said in a statement.
A change.org petition calling for Australia to become a republic has attracted 3500 signatures since Friday.
ACT Chief Minister Andrew Barr believes Australia's ties to the monarchy reflect a nation of the past.
"It's time for us to grow up and stand on our own two feet," he said.
Queensland Premier Annastacia Palaszczuk believes it's time for Australia to be led by one of its own while her South Australian counterpart Jay Weatherill thinks becoming a sovereign nation would profoundly change Australian mindsets.
