If the official count of the same-sex marriage survey matches myriad opinion polls, same-sex Australian couples will be able to marry by Christmas.
"That's the goal," Prime Minister Malcolm Turnbull vowed ahead of the Australian Bureau of Statistics announcing today which way more than 12 million people voted on the issue.
Mr Turnbull, who touched down in Canberra after five days in southeast Asia, has slapped down a late push by conservative colleagues to water down anti-discrimination laws if the "yes" vote prevails.
Nearly 80 per cent of eligible Australians took part in the voluntary poll, a return rate that compares more than favourably with the 91 per cent who voted at the compulsory 2016 federal election.
Various opinion polls point to a majority 'yes' vote, possibly as high as 60 per cent.
Greens senator Janet Rice, who has a transgender wife, believes she is the last person to "absolutely, definitely" predict a 'yes' win.
"But the polls have been pretty consistent and it really does seem that in commentary right across the political spectrum the expectation is that there will be a 'yes' vote," she said.
Shock ballot-box results from Brexit to the US presidential election have campaigners wary of published opinion polls.
Nevertheless, discussions are well under underway as to how same-sex marriage might be legislated.
A "NO" supporter holds a banner at a Coalition for Marriage campaign launch in Melbourne. Source: AAP
A private bill, proposed by West Australian Liberal senator Dean Smith, has been labelled the "starting point" by senior government ministers.
It will be supported by Labor and the Greens even though the minor party plans to present amendments.
A second private bill, containing more protections for religious protections and conscientious objection, is being pushed by conservative coalition MPs, many of whom campaigned for a 'no' vote.
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Labor Senate leader Penny Wong condemned the move.
"If the Australian people do vote yes, they're not going to look kindly on the same group of people who have urged a 'no' vote not accepting the outcome and trying to delay further," she said.
"Australians voted for equality. They didn't vote to license more discrimination and that is what the Paterson bill does."
Attorney-General George Brandis has labelled same-sex marriage a "very, very important human rights reform".
"But also, we should respect another human right and that is freedom of religious belief," he said.
That will be all for nothing - or the $122 million cost of the survey - if a 'no' vote prevails.
Olympian Ian Thorpe is quietly confident the same-sex marriage survey will deliver a majority 'yes" vote.
"Personally, I want to see this," he said at a Marriage Equality event in Sydney ahead of the 10am announcement of the result.
"We are cautiously optimistic at this stage."
The five times swimming Olympic gold medal winner came out as gay in 2014.
Other high-profile Australians attending the Sydney Marriage Equality gathering include comedian and actor Magda Szubanski, former prime minister Tony Abbott's sister and Sydney councillor Christine Forster and Sydney Lord Mayor Clover Moore.
A parallel event is being held in Melbourne with federal Opposition Leader Bill Shorten.
Szubankski said she was praying for a 'yes' result.
"It is about someone like me having the right, but also the privilege and the responsibility of marriage in marrying someone of my own age," she told Seven Network.
