Sparks have flown in the first election year debate, with Mana leader Hone Harawira swearing at the host and threatening National MP Chris Bishop.

At the Auckland University debate on Thursday night, Mr Harawira was defending his policy that immigrants should buy a newly-built house when moving to New Zealand.

Newshub political editor and debate MC Patrick Gower asked Mr Bishop what he thought.

"It's the worst sort of politics to blame foreigners for our problems," Mr Bishop said, when Mr Harawira interjected.

"Nobody over here is blaming foreigners," he said.

Mr Bishop fired back, taking the debate on a different tangent: "Hone, you said before you worked hard. The last time you were an MP, you turned up to Parliament so little, we had to pass a special law to make sure you got fined for not turning up."

He won cheers from the audience, before Mr Harawira raised his voice. "You don't have the courage to get up and speak for yourself, and that's why you're in the National Party, because you let yourself be told what to do."

Mr Harawira said an MP should fight for his people, "and if you won't do it, get the hell out of Parliament!"

ACT leader David Seymour chipped in to defend Mr Bishop: "That's right, Bish does what he's told - when he has to be in Parliament, he's actually in Parliament."

Mr Bishop then accused Mr Harawira of going on a private jaunt to Paris while on a taxpayer-funded trip to Europe in 2009.

Gower tried to bring order back to the fiery tit-for-tat, but Mr Harawira wasn't having any of it.

"Paddy! If this is a housing question you should have f*cking slapped him down the minute he started making a personal attack. He's turned it into a personal attack and if he wants to go down that track, let's do it."

But Mr Harawira then got back to the issue.

"This is not an attack on foreigners."

As he talked, Mr Bishop continued to interject, until Mr Harawira threatened him.

"Sit down Chris Bishop, or you could end up in a place you don't want to be."

Gower restored order, saying: "We're all just going to take a little breath here," before he went to Greens MP James Shaw to help simmer things down.

Newshub.

