CANBERRA - More than 61 percent of Australians have voted in favour of legalizing same-sex marriage, it was announced on Wednesday.

The Australian Bureau of Statistics (ABS) announced the results of the Australian Marriage Law Postal Survey on Wednesday with 7.8 million respondents, or 61.6 percent, voting in support of same-sex marriage and 4.9 million, or 38.4 percent, opposing it.

More than 12.7 million eligible voters, or 79.5 percent, took part in the optional postal survey, a turnout the ABS described as a great result.

Five of Australia's states and both its territories returned a yes vote of more than 60 percent, with New South Wales (NSW) the only exception at 58 percent.

As the survey was non-binding it does not mean that same-sex marriage has been legalized but Prime Minister Malcolm Turnbull said a bill legalizing the practice would be introduced to parliament before Christmas.

"They have spoken in their millions and they have voted overwhelmingly yes for marriage equality," Turnbull told reporters in Canberra on Wednesday.

"And 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 asked to do and get this done. This year, before Christmas -- that must be our commitment."

Of Australia's 150 electoral divisions, 133 returned a majority yes vote with the seats of Melbourne and Sydney being strongest in favour at 83.7 percent each.

Bill Shorten, leader of the Opposition Australian Labor Party (ALP), described it as "a fabulous day to be an Australian."

"Today we celebrate, tomorrow we legislate. What this shows is unconditional love always has the last word," Shorten told a large crowd that gathered to hear the result in Melbourne.

Dean Smith, a government Senator who has drafted a bill that would legalize same-sex marriage, said the result was the "strongest electoral mandate we have seen."

"It's now up to parliament to do what it's always been expected to do -- to legislate." said Smith.

The Australian Capital Territory (ACT) was most supportive of gay marriage with a 74-percent yes vote followed by Victoria (64.9 percent), Western Australia (63.7 percent) and Tasmania (63.6 percent).

Eric Abetz, a senator for Tasmania and prominent figure in the "no" campaign, said he regrets the result but would respect it.

"Changing a fundamental societal institution that pre-existed the nation-state is something which should rightly be decided by the people as a whole and it has been with a very strong turnout despite claims from many quarters that this process would fail," Abetz said.

The NSW seat of Blaxland, which is held by the ALP, had the strongest opposition to the practice with 73.9 percent voting no.