Almost 5 per cent of all marriages of New Zealand residents were between same-sex couples in the first four months after gay marriage became legal.
The figure is much higher than expected and indicates that gay marriage may be much more popular than civil unions. Civil unions between same-sex couples accounted for only 1.1 per cent of all marriages and civil unions in the period from 2005, when civil unions became legal, to the end of 2012, before the gay marriage law was passed.
However, it may be only a temporary phenomenon as gay couples who could not legally marry until last August 19 rushed to "catch up" with the rest of the population.
Figures provided by the Registrar-General of Births, Deaths and Marriages, Jeff Montgomery, show that 131 same-sex couples who did not live in New Zealand also married here in the four months to December 19, including 88 Australian couples.
"We expect to continue to see a number of overseas same-sex couples choosing New Zealand for their weddings, particularly given recent Australian court decisions," Mr Montgomery said.
The Australian High Court last month struck down a law passed by the Australian Capital Territory that had briefly legalised gay marriages in Canberra.
Including the foreigners, there were 335 same-sex marriages in New Zealand in the four months to December 19 - with 178 between women and 157 between men.
There were 4,506 marriages between men and women and two between people of "indeterminate" gender, which covers people transitioning through a sex change or with no defined gender.
Excluding the indeterminate marriages, same-sex marriages made up 6.9 per cent of all marriages, and 4.7 per cent of marriages of New Zealand residents, in the four-month period.
Dr Peter Saxton, of Auckland University's Gay Men's Sexual Health research group, said the figures were not a surprise given a range of estimates of the prevalence of homosexual orientation.
"I think about 5 per cent is in the ballpark when you factor in a bit of catch-up," he said.
Last year's Census found that only 0.9 per cent of all couples were of the same sex, up only slightly from 0.7 per cent in 2006, but this is believed to be an under-estimate because many gay couples are likely to have described themselves on Census forms as flatmates rather than partners. An Auckland University survey of high school students last year found that 3.8 per cent said they were attracted to the same sex or both sexes.