There were loud cheers, hugs and sustained clapping in the lower House of Representatives when all but four MPs voted in support of marriage equality, after the upper house Senate passed the bill 43-12 last week.
"What a day for love, for quality, for respect! Australia has done it," Prime Minister Malcolm Turnbull told the House.
The final step is for the Governor-General Peter Cosgrove, the Queen's representative in Australia, to ratify the law, which will likely take place within days.
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