New Zealand would consider sending armed forces troops into Fiji if they were needed to stabilise peace as part of a multi-lateral action, Prime Minister John Key said.

The Government was not "sitting here planning today to do that" but would consider it if the need arose, he told TV One's Breakfast show.

"If it was part of a multi-lateral effort to stabilise peace in a dangerous situation in Fiji of course New Zealand would consider that (sending in troops)," he said.

"It's very concerning in Fiji ... I think it's tragic actually."

He said there was always the threat of a fight back from the Fijian people.

Foreign Minister Murray McCully said yesterday the Government was considering strengthening sanctions against Fiji but would not impose tourism and trade restrictions.

"Sacking the judges, clamping down on personal freedoms, media freedoms, it doesn't get much worse than that," he said.

"That's a traditional mould for a military dictator and it hasn't had a happy ending anywhere in the world."

Fiji's President Ratu Iloilo scrapped Fiji's constitution and fired the judiciary earlier this month after three Appeal Court judges ruled the military takeover in 2006 was illegal.

Self-appointed Prime Minister Commodore Voreqe (Frank) Bainimarama was re-appointed prime minister and immediately issued decrees which included media censorship and immunity from prosecution for soldiers.

His explanation has been that he won't hold elections until reforms have been implemented to change the system, and the timeline has been extended to 2014.

The Pacific Island Forum, the Commonwealth and the European Union are urging Cdre Bainimarama to return Fiji to democratic rule but he has so far ignored them.