Australia is being urged to "seize this moment" in the republic debate after almost all state and territory leaders signed a declaration calling for an Australian head of state.
Australian Republican Movement chair Peter FitzSimons says it's a "no-brainer" that Australia will become a republic, insisting support for the push is phenomenal.
He says the support from political leaders, including Prime Minister Malcolm Turnbull and Opposition Leader Bill Shorten, was no less than a "declaration of desired independence".
The only state leader who declined to sign was West Australian Premier Colin Barnett.
Mr FitzSimons said he was "bemused" by Mr Barnett's refusal to sign, saying the premier sent him a note insisting he was committed to the republican movement but wasn't keen to sign yet.