Nearly 60 percent of Australian voters have already cast their ballots in a controversial postal survey on whether to legalise same-sex marriage, officials said Tuesday.
With more than a month to run in the postal vote that began on September 12, an estimated 9.2 million people, or 57.5 percent of the electorate, had returned their forms as of last Friday, the Australian Bureau of Statistics said.
The result will not be published until November 15, a week after the poll closes, but campaigners from both the "yes" and "no" camps have welcomed the high response.
"This turnout is a powerful sign of how the millions of respectful conversations that have taken place at kitchen tables, workplaces and across every community have motivated people and allowed them to see that marriage equality is not a what, it is a who," co-chair of the Equality Campaign, Anna Brown, said in a statement.
Polls indicate that the "yes" camp is leading the vote but advocates are cautious of complacency.
"Over a million Australians living overseas still need to return their surveys as well, either through the post, online or trusted individuals," Brown added. "It is vital every Australians has their say."
The leading voice of the "no" campaign was also pleased with the early voter numbers.
"The high turnout demonstrates that the Australian public understand the gravity of the decision before us, and that they know it has consequences for everyone," said Lyle Shelton, spokesman for the Coalition for Marriage.
"This is consistent with the overwhelming number of calls and emails from people all over Australia who are concerned about how same-sex marriage will impact on schools, freedom of speech and freedom of religion."
The Australian count looks set to overtake the turnout for the 2015 Irish same-sex marriage referendum, which saw about 60 percent of voters take part.
If the "yes" vote wins the ballot, the government has pledged to hold a parliamentary vote on changing the marriage laws. It will not do so if there is a "no" outcome.
The conservative government called for the postal vote after its election promise of a national plebiscite was twice rejected by the Senate, parliament's upper house.
The campaign has proven divisive, with big business, major sporting codes, religious bodies and even international music artists criticised for taking sides on the issue.