Wellington: New Zealand on Monday supported changing royal succession rules to allow Prince William and Kate Middleton's first born to become monarch regardless of its gender.

Prime Minister John Key said that New Zealand backed a proposal to scrap the principle of male primogeniture, which means that the first born son would be next in line to inherit the throne, even if he had an older sister.

"New Zealand supports that view but I don't know whether those changes will happen anytime soon" he said.

Key, who will be in Britain for William and Kate's April 29 wedding at London's Westminster Abbey, said he doubted Queen Elizabeth II would raise the issue during a scheduled lunch at Windsor Castle.

Britain's Deputy Prime Minister Nick Clegg, who has described the current system as old fashioned, has raised the issue of changing succession rules. He is responsible for constitutional reforms.

The chairman of New Zealand Republican Movement, Lewis Holden, said most countrymen would be aghast that such a sexist succession rule was used to appoint their head of state.

New Zealand, a former British colony, still recognizes the Queen as the country's head of state.

Holden said, "The changes will keep the position of New Zealand's head of state in the hands of a British aristocratic family on the other side of the world” calling for a referendum to decide the country's head of state.