On Sunday, 20,000 people took to the streets of Sydney in support of a Yes vote, occasionally meeting opposition demonstrations bearing signs in favour of "traditional" and "natural" marriage.
The positive result for the equality campaign comes as the Australian Bureau of Statistics begins to send survey forms to 16 million Australians to gauge their thoughts about changing the marriage laws.
Though the survey does not have the power to change the law, it could lead to a vote in parliament.
The ballot's unusual format was decided after the election promise of a national plebiscite was rejected twice by parliament's upper house.
Of those certain to post their ballot papers back, 70 percent said they would support gay marriage.
The survey goes ahead after the High Court of Australia last week dismissed two objections to the poll. "We can win this thing!"
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Even as forecasts showed the storm's center could enter Georgia far inland after churning up the Florida peninsula, Gov. Almost 7 million people in the Southeast were warned to evacuate, including 6.4 million in Florida alone.
But the government is refusing to release a draft bill until after the people decide whether the parliament will consider any bill. "We can climb this mountain".
Despite growing support among sporting bodies for marriage equality and homosexual rights, few Australian athletes have come out as gay.
Turnbull, a political moderate who supports marriage equality, is opposed by some in his own Liberal-National governing coalition. Hundreds of "no" campaigners marched the day before, on Saturday, arguing that changes would infringe on religious freedom and children's rights.
Andrew Pasco, one of thousands of people who packed the streets of Sydney for the "yes" campaign rally on Sunday, said he was anxious the polarising debate could discourage moderate Australians from voting.
But "yes" campaigners have warned that the method of collecting votes, via the postal system, could be less effective at engaging younger tech-savvy Australians, who are seen as more supportive of changing the laws.
People will have until November 07 to cast their vote by mail and results of the voluntary poll are expected on November 15.