The poll which was conducted by the country’s Bureau of Statistics triggered emotional celebrations by gays and lesbians and marriage equality supporters.
Almost 62 percent of the 12.7 million people who participated voted “yes” to the question “Should the law be changed to allow same-sex couples to marry?”
Just 38.4 percent voted “no”, according to the Australian Bureau of Statistics, which carried out the poll.
Nearly 80 percent of eligible voters took part in the poll, with the “yes” vote winning a majority in all of Australia’s states and territories.
The result appeared to have ended more than a decade of divisive debate.
Political leaders immediately took the first steps to enshrine the historic shift in law.
Within hours of the vote result, Dean Smith, a Senator from Turnbull’s Liberal Party who is gay, introduced a bill that would legalise gay marriage while allowing religious institutions and clergy to refuse to celebrate same-sex unions if it conflicts with their beliefs.
Thousands of marriage equality supporters took to parks and squares across the vast continent, hugging, dancing and singing under clouds of glitter when the results of the two-month-long postal survey were announced.
“This means everything, this means everything,” shouted Chris at a huge rally in Sydney, fighting back tears and hugging his partner Victor.
“It has been fantastic. I have been with my partner for 35 years and he was so joyed up that he burst into tears,” added another reveller, Gerry.
Irish-born Qantas Airlines chief Alan Joyce, who is openly gay and campaigned strongly for the “yes” campaign, also fought back tears as he spoke of his delight.
“I was so proud of Ireland in May 2015 when they became the first nation in the world to vote for marriage equality… But today I am even more proud of Australia, the country of my selection,” he said in Sydney.
Prime Minister Malcolm Turnbull, a moderate conservative who backed the “yes” camp, hailed the result of the non-binding vote and vowed to move a bill in favour of marriage equality by Christmas.
Australians “voted yes for fairness, yes for commitment, yes for love,” Turnbull said at a press conference in Canberra.
“Now it is up to us, here in the Parliament of Australia, to get on with it. To get on with the job the Australian people have tasked us to do and get this done, this year, before Christmas. That must be our commitment.”