More than half of eligible Australians have cast their ballots in the same-sex marriage survey, in what Prime Minister Malcolm Turnbull has celebrated as a great outcome.
The Australian Bureau of Statistics received roughly 9.2 million ballots, or 57.5 per cent of the forms it sent out, by Friday afternoon.
Mr Turnbull believes the estimate shows Australians wanted to have their say after Labor blocked a promised plebiscite.
"I think it is a ringing endorsement of the government's decision to give every Australian their say on this issue," he told ABC radio on Wednesday.
Mr Turnbull expects the very high participation rate to increase with more than four weeks to go before the ballot closes.
Finance Minister Mathias Cormann, who is spearheading the survey, said the return rate showed Australians were embracing the opportunity.
"I am very confident that the ultimate outcome of the survey will have great authority. It will come with the great authority of the Australian people and will be acted upon by the Australian Parliament," he said.
Campaigners from both sides of the debate insist the fight is far from over, with the Coalition for Marriage vowing to push on tirelessly until votes close.
"Half of the country is yet to make up its mind - this conversation is still wide open," spokesman Lyle Shelton said.
Marriage equality campaigner Alex Greenwich is urging those who have filled out their forms but not yet returned them to post them promptly.
Cabinet minister Darren Chester, who backs same-sex marriage, believes there will be a resounding 'yes' vote across Australia.
"As I travelled around suburban and regional areas, the feedback from people is they want to get on with it," he said.
"They don't want to be shouted at by the yes or no campaign, they want to have their vote and get on with it. I think the result will be quite a compelling yes vote."
The ABS will provide an updated estimate every week until the postal survey closes on November 7, with the results to be published on November 15.
