New Zealand's politicians are expected to back gay marriage in a vote tonight, making it the 13th country to do so.
Gay marriage advocate Rodney Croome says a survey by his organisation, Australian Marriage Equality, has found more than 1000 couples plan to travel to New Zealand to tie the knot.
Kiwis would now get a slice of the estimated $700 million spent by Australian same-sex couples on their weddings, he said.
Most Australian same-sex partners would prefer to marry the person they love in the country they love, Mr Croome said.
"But now that marriage equality is only three hours away there will be a flood of couples flying to New Zealand to tie the knot and spend their money," he said in a statement.
New Zealand was set to reap a massive economic dividend from the wedding spend of those Australian same-sex couples who were tired of their country's failure to act.
Last year, an attempt to legalise gay marriage failed in the Australian parliament, with Prime Minister Julia Gillard opposed to the move, and Opposition Leader Tony Abbott refusing coalition MPs a conscience vote.
