The legalisation of gay marriage in New Zealand does not eliminate every shred of legal inequalities for gay couples, with a grey area still remaining around adoption.
Same-sex married couples could also run into problems when seeking visas in other countries, legal experts warned after the Marriage (Definition of Marriage) Amendment Bill passed into law this week.
The bill was given royal assent yesterday, and gay and transgender couples will be able to marry from August 19.
Victoria University family law expert Bill Atkins said many of the legal imbalances between married and de facto couples and gay and straight couples had already been addressed in the law.
"In some ways the bill is the icing on the cake and a lot of the issues where same-sex couples and de facto couples have been treated differently have been sorted out by changes made before this."
"In many ways this was the last big change apart from some problems with ... other couples and adoption."
One of the consequences of the historic law change was that same-sex couples who married would be able to jointly adopt a child. Previously, a gay individual could adopt a child, but a gay couple could not.
Family law expert Catriona Doyle said this would have the most significance for same-sex couples who commissioned a surrogate child. Both of the parents could now be legally recognised as a parent of the child.
But the law change did not completely erase inequality with regard to adoption. Unlike straight de facto couples, gay de facto couples could not jointly adopt. And neither gay nor straight civil union couples qualified as spouses, and therefore could not adopt.
Ms Doyle said that meant that a single gay person had a better chance of adopting a child than a gay couple in a committed but unmarried relationship.
Green MP Kevin Hague has drafted a private member's bill which would overhaul adoption law and remove all restrictions to adoption by gay couples.
Professor Atkins said that married gay couples could face some barriers when travelling to countries which did not recognise same-sex weddings.
"There are some countries which won't accept a same-sex marriage - I'm thinking in particular of Islamic countries. There might still be some problems in that area, despite the change in the law."
Most New Zealand visa applications were made for Britain and the United States. Although British politicians were considering legislation to legalise gay marriage, it was still illegal in most jurisdictions of the US.
Under US federal law, a gay husband or wife did not qualify as a spouse and could not enter the country on their partner's visa. However, they could get a visitor's visa which was specially annotated to last for the length of their partner's work permit.
Same-sex married couples who moved to New Zealand would automatically have their marriage recognised and get the legal privileges of married couples, as long as one of the couple was from a Commonwealth country.
Under previous law changes, gay couples already qualified for other privileges such as paid parental leave, and property rights after a break-up.
• In the latest Listener, gay writer Peter Wells explains why he won't be getting married.