The federal parliamentary debate to legalise same-sex marriage could begin as early as Thursday if the 'yes' vote prevails in the postal survey.
A cross-party group of senators - led by Liberal Dean Smith and supported by senior Labor figure Penny Wong, amongst others - will introduce a private bill to the upper house on Wednesday, just hours after the survey result is announced.
Debate would start on Thursday morning, the Senate's usual time for considering private bills.
"There's been a long road and there's still further fights down the track," Senator Wong told reporters in Canberra.
The results of the postal survey, in which 12 million Australians have had their say, will be announced at 10am on Wednesday.
Senior government ministers have labelled the Smith bill a good "starting point" for parliament's consideration.
Liberal Democrats senator David Leyonhjelm is planning a number of amendments.
"We have to recognise that there are some people who are conscientiously opposed to same-sex marriage," he told reporters.
"We do not want a dictatorship of the majority in this country."
The Greens will also propose a number of amendments, but won't jeopardise passage of the bill if they fail to garner support.
"At the end of the day, we are in support of getting a bill through parliament that will mean we can have marriage equality," Greens senator Janet Rice said.
Crossbench senator Derryn Hinch is running a sweep on the survey result, to help raise money for homeless people.
The prime minister's office declined to join but contributed $50 to the cause, he said.
Independent Fraser Anning was among the conservative punters, nominating a 54-46 per cent 'yes' vote.
At 70-30 'yes', Labor senator Doug Cameron was only too glad to share his optimism.
"I note that I was the one saying it was going to be the highest vote," he said.
© AAP 2017