Thousands of Australians are expected to flock to New Zealand, which on Wednesday night passed laws approving same-sex marriage.
"I think it is going to be huge. It will definitely boost tourism to New Zealand with thousands and thousands going over to get married or as wedding guests," said Reece Farmilo, the owner of Sydney's Out Travel, one of the biggest gay travel agencies in Australia. "We've already had calls this morning from people wanting to go and from wedding planners based in New Zealand who want to work with us."
New Zealand became the 13th country in the world to approve same-sex marriage and the first in the Asia-Pacific region.
Australian Marriage Equality national director Rodney Croome said same-sex marriage could provide a $700 million boost to the Australian economy but instead much of that money would be spent across the Tasman.
"An immense opportunity is being lost by the federal government here," he said. Same-sex marriage is also recognised in nine states in the US, including New York, where mayor Michael Bloomberg said it brought $US259 million ($251 million) of economic benefits in the first year after the law was introduced in 2011.
There are reports more than 200,000 wedding guests travelled from outside the city to attend same-sex wedding receptions, and more than 235,000 hotel room nights were booked in the first year.
Tourism New Zealand's general manager for Australia, Tim Burgess, said: "We think it will bring a positive impact in visitor numbers from Australia, especially because of the close relationship and proximity of the two countries.
"New Zealand is already the No.1 holiday choice for Australians going overseas [1.15 million visited last year], so why not the No.1 same-sex marriage destination?"
Auckland revived a gay pride event this February after a 12-year absence, but the longest-running event on the Kiwi gay calendar is the annual Queenstown gay ski week which started about a decade ago.
The Queenstown organisers, Sally and Mandy Whitewoods, said on Thursday they were "over the moon" with the new laws.
"This is such an amazing achievement for same-sex couples in New Zealand and across the globe," Sally Whitewoods said. "We're already fielding Facebook posts, emails and calls from friends who're thinking about heading over to New Zealand to get married."
Tourism authorities in Wellington are already capitalising on the expected boom by launching a competition that gives couples the chance to win a $NZ20,000 package to the city, including return flights for the wedding party, a wedding planner and accommodation. The competition will go live on WellingtonNZ.com on April 27.
The legislation is expected to come into effect in New Zealand in August but Australian law does not recognise same-sex marriages entered into overseas.
Other countries to legalise same-sex marriage include Uruguay, which passed laws last week, as well as Canada, South Africa, the Netherlands, Belgium, Spain, Argentina, Norway, Portugal, Sweden, Iceland and Denmark.