Where do potential Prime Ministers stand on North Korea?

Tensions are boiling over between North Korea and the United States, with respective leaders Kim Jong-un and Donald Trump both issuing dire warnings of the risk of war.

North Korea recently sent another worrying warning to the world, saying that nuclear war could "break out any moment".

So where do New Zealand's two potential leaders stand on our involvement with the conflict?

Political editor Patrick Gower put the question to them as part of the Newshub Leaders Debate during this year's election campaign.

"It's 3am, North Korea and the United States are at war, and your phone rings," he quizzed. "It's Donald Trump asking you to join him in war against North Korea. What do you say?"

National leader Bill English:

"I would say to him that, while we've had a long friendship with the US, we make our own decisions on our own interests and that if he has a specific request, then we would consider it.

"The basic friendship with the US is probably less important in that case than stability for the Asia/Pacific.

"I wouldn't give him a commitment over the phone. That would not be fair, because the New Zealand public would need to understand, particularly if there was some kind of military commitment, about which we're very, very careful.

Labour leader Jacinda Ardern:

"The response I would give to Donald Trump would be the same one I'd give in the situation right now - the UN needs to be brought in.

"China is a critical part of resolving the dispute we have now - let's resolve it before it escalates even further.

"I agree with a lot of what Bill said on that... you've got to forge your own path. We would go back to the UN - we've always taken a multi-lateral approach and done what's in the best interests of New Zealand."

Coalition could change stances

Auckland University international relations professor Stephen Hoadley says adding coalition negotiations to the mix could pull each party's stance "a little closer to the centre".

"Any government would condemn what North Korea is doing and retain a distance... as long as the three partner governments in northeast Asia [South Korea, Japan and Taiwan] don't make extraordinary demands on New Zealand.

"Labour would still be taking advice from Ministry of Foreign Affairs, whose staff won't change under a new government."

Prof Hoadley says New Zealand is typically wary of getting involved, but is at the forefront of anti-nuclear legislation and is quick to condemn any nuclear testing.

Under the ANZUS Treaty, in effect since 1952, Australia is obliged to back the US in the event of an attack like that threatened by North Korean leader Kim Jong Un on Guam.

"In terms of defence, we are joined at the hip," Australian Prime Minister Malcolm Turnbull said of their relationship.

US-New Zealand obligations under the treaty have been suspended since 1984.