Same-sex marriage postal survey: 'Yes' wins

Australians have voted in favour of legalising same-sex marriage, saying "yes" to same sex marriage by a substantial margin of 61.6 per cent to 38.4 per cent.

In the Farrer electorate, which takes in Griffith, the yes vote was lower, but still a majority at 55.2 per cent. 

Almost 80 per cent of eligible voters participated in the unprecedented voluntary postal survey, giving the verdict an authority unmatched by most elections globally.

It means Australia is poised to join 25 other countries that have granted marriage equality to gay couples, including the US, Canada, New Zealand and the United Kingdom.

At street parties across the country, gay and lesbian Australians cheered, danced and embraced as the results were announced by the chief statistician on Wednesday.

Kerry Aldred, who is organising the first ever Gay and Lesbian Mardi Gras in her western NSW country town of Hay, said:

"I personally am so relieved that the result was in favour of the yes! I have many friends that this survey has affected in far too many ways, so having this win is awesome."

"Now we need to see the bill pass presented by Senator Dean Smith, then we can really celebrate!"

The result is said to be a significant victory for Prime Minister Malcolm Turnbull, of the ruling centre-right Coalition, who is a longstanding supporter of same-sex marriage and firmly believed the "yes" vote would prevail.

"Love has had a landslide victory," declared Alex Greenwich, co-chair of the Equality Campaign, from a public gathering in Sydney. "Getting to this point has not been easy, but rarely in your life can you celebrate with such pride overcoming adversity to make history."

Mr Greenwich said the campaign's support and momentum had exceeded all expectations, and the result had delivered "an unequivocal mandate" for politicians to vote through the change by the end of the year.