Anxious leaders in New Zealand are not supporting, yet not criticising, the United States' strikes on Iran as it seeks a justification of the raids.

Donald Trump's administration entered the spiralling Israel-Iran conflict on Sunday with bombing raids on three facilities.

Ahead of the operation, New Zealand Prime Minister Chris Luxon said the right response "cannot be more military action", and after the attacks, he said his position remained the same.

"We want to see a peaceful secure and stable Middle East. The way to get there is a political solution rather than military action ... it's through dialogue and diplomacy," he said.

New Zealand, like Australia and the US, is steadfast that Iran cannot be allowed to establish a nuclear arsenal.

However, Foreign Minister Winston Peters said that did not extend automatically to support for the US strikes as that would only be "justified by the level of nuclear preparedness by Iran".

Judith Collins, Christopher Luxon, Winston Peters. – file

"We'd be very wise to keep our counsel and find out the facts, get a proper analysis and ensure that what we're talking about is true," he said.

Peters, in his third stint as foreign minister in a political career lasting half a century, said the "level of inflection we're talking about, potentially" was akin to the 1962 Cuban Missile Crisis.

"The worst thing about a crisis is what you see is not always what you get," he said.

"It could be far, far, far, far worse and that's the tragedy we might face, we just don't know."

Defence Minister Judith Collins has sent a Hercules aircraft under NZDF command to the region to help airlift citizens in the war zone.

New Zealand already has dozens of military personnel engaged in the region, and deployed a small group to assist as part of a US-led coalition to stop Houthi strikes on international shipping in the Red Sea.

Both Peters and Luxon, in Europe this week for a NATO summit, have previously spoken of New Zealand's concern of a world where the rules-based system is "giving way to power".

"A return to a world where raw power is the primary determinant in advancing states' interests would be a harsh world indeed,"  Luxon told the Lowy Institute in Sydney in 2024.

In Belgium, Luxon said he wanted conflicts resolved through negotiation.

"New Zealand doesn't want to see a nuclear-armed Iran destabilising its neighbours," Luxon said.

"We don't want to see Gaza under Israeli occupation. We don't want to see Hamas holding onto hostages.

"The answer in all of those cases, in all of the conflicts in the Middle East, is dialogue and diplomacy not military action."

New Zealand also announced a fresh contribution to Ukraine's defence, offering $NZ16 million in its war against Russia.