Prince William arrives at the new Supreme Court building. Pic: NZPA

Wellington, Jan 18 NZPA - Members of the Republican Movement unfurled a banner stating "It's time for a republic" today outside the Supreme Court in Wellington as Prince William arrived to officially open the building.

The group also mounted a noisy protest when the price arrived at the site, prompting an angry response from supporters of the man who is second in line for the throne.

The demonstration was to highlight that New Zealanders were capable of choosing a head of state of their own, the movement's chairman Lewis Holden said.

"Prince William might be a nice guy, but it should be a New Zealander, chosen by New Zealanders, opening our highest court of appeal."

"It has cost New Zealand taxpayers $200,000 to bring Prince William out to New Zealand.

"Monarchist claims that this figure has been paid off with free advertising are nonsense. Prince William had a gap year in Chile, giving that republic a lot of free publicity. The Queen visited Trinidad and Tobago last year, a republic within the Commonwealth, giving that country free press also," Mr Holden said.

Parliament is set to vote on Green Party MP Keith Locke's Head of State Referenda Bill in March.