More than half of registered voters have returned their same-sex marriage ballots, as 'yes' supporters vow not to waste a single day's campaigning until the controversial national survey closes.
The Australian Bureau of Statistics estimates it has received 9.2 million (57.5 percent) of the 16 million survey forms since the ballot on whether people can marry who they love was issued two weeks ago.
The ABS's published estimate -- which is based on Australia Post's assessment of the number of containers -- is the first of several updates to come ahead of the November 7 deadline for returning the form
"We hope that this update will serve as a reminder to those who have not submitted their form to do so promptly if they wish to have their say," said ABS Deputy Statistician and Taskforce Lead Jonathan Palmer.
Yes campaign spokesman Tiernan Brady told reporters the 'yes' side would continue at full speed, and he expected the vote to get much higher.
"So we can have a survey that reflects the values of the Australian people, who have long since believed it is time for marriage equality," he said.
"People understand the power of their vote, they know how important this is.
"It's not a normal political question about taxes, higher taxes or lower taxes, or whether a motorway should go here or there. It's about the very dignity of people in our communities, people who love our communities just as much as we do."
The offical estimate came after the 'yes' and 'no' sides released polling of their own, and each with wildly different estimates.
On Monday a poll conducted for The Equality Campaign found 77 per cent of the nation's 16 million enrolled voters had returned their forms.
Another poll commissioned by the Equality Campaign showed Australian women as leading the way in supporting a YES vote.
That poll showed almost eight in ten women aged 25 to 44 are voting YES in the marriage equality postal survey.
"Women play such an important role in guiding current and future generations, and as mothers, grandmothers and aunties we intuitively understand why fairness is important," Equality Campaign's Janine Middleton said.
"Like LGBTI Australians, women have also had to fight for equal treatment."
In August an enrolment surge led to extra 98,000 Australians putting their names down to vote in the marriage law postal survey.
That surge was driven by young people, women and inner-city residents, The Guardian reports.
The results of yet another poll published two weeks ago showed a possible shift towards the 'No' campaign, with support falling from 63 to 57 per cent amid arguments over advertising tactics.
Psephologist Kevin Bonham told the ABC ahead of the ABS releasing its update he had originally expected a half to two-thirds response rate.
"There may be a novelty component to it for some people," he said.
"It's not something they do all the time, so it's not like being dragged to the ballot box again and again."
He said if turnout is over 80 percent and one side wins convincingly, then you could be confident that that side is most preferred by voters.
On the weekend former Prime Minister John Howard took out a full page newspaper ad urging the Federal government to spell out protections for parental rights, free speech and religious freedoms.
But Family Court Chief Justice Diana Bryant told The Australiansame sex marriage would have no effect on how the Family Law Act is applied to children.
"What you want for children is a stable, loving and caring relationship in which they are brought up," she told the national broadsheet.
"It really doesn't matter who their parents are as long as they have all of those aspects, and if they do, there is absolutely no reason why there should be any discrimination in my view."
Announcing its support for marriage equality on Tuesday, The Royal Australian College of General Practitioners (RACGP) said it recognised the polarisation of communities and significant distress that a public vote on marriage equality has LGBTIQ Australians.
"The RACGP acknowledges that discrimination, bullying and harassment of LGBTIQ people has a severe, damaging impact on mental and physical health outcomes for affected individuals, their families and community," the RACGP said.
The ABS is expected to announce the result on November 15.