New Zealand First leader Winston Peters has reacted furiously to being asked about leaking and fraud investigations on live television.

In a fiery clash with Q+A broadcaster Jack Tame this morning, he accused TVNZ of lying and ambushing him about topics which he had not prepared for.

"I regret coming here this morning, to stop off my campaign, to come along to see some junior who thinks he's going to play Billy the Kid," he told Tame.

Peters said he had expected to come on the TVNZ show to discuss Covid-19 and live exports of livestock.

But he reacted strongly when he was asked about other issues, including whether anyone related to his party was responsible for leaking documents about the Green Party's controversial backing for a private school.

"If you wanted to know the answer to that question, why didn't you ask me last night or this morning and I could have got it for you," Peters said.

The NZ First leader and Deputy Prime Minister repeatedly refused to answer the question.

"You're not a lawyer," he told Tame. "Stop playing silly games, I'm telling you."

During the heat of the discussion, Peters referred to Tame as "James" on five occasions.

"My name is Jack, Mr Peters," the broadcaster said.

The interview sparked widespread reaction on social media, some siding with Tame and others with Peters. One person labelled it a "train-wreck".

Peters also reacted angrily when he was asked about arranging for two of his friends to get a taxpayer-funded trip to Scott Base in Antarctica.

"Don't use the power of the state, paid for by the taxpayer, to try and take a political party apart … with a bit of old-fashioned dirt," he said.

"If you wanted information on that, I could have given answers provided to Gerry Brownlee and everyone who has asked in the last few months. But no, you thought you'd come down and hijack me."

Peters was challenged about the decision to spend $10.5 million on a horseracing track in Christchurch through the Provincial Growth Fund. He was asked how much New Zealand First had received from the horse-racing industry in donations.

"You can keep on talking as long as you like," Peters said. "But I think it's a disgrace that a taxpayer-owned operation like TVNZ is behaving like this."

Tame stood by his line of questioning, saying it was six weeks from the general election and integrity was a central issue for voters.

He also asked Peters whether he had been interviewed by the Serious Fraud Office over its investigation into electoral donations.

The SFO is investigating an entity called the New Zealand First Foundation, which has bankrolled Peters' party.

Peters refused to say whether he had been interviewed by the SFO. Tame again said the question was about integrity.

"Why did you lie about it then?" Peters said. "You and your producer flat-out lied about what this show was about."

The interview then calmed down as it returned to an area Peters was more comfortable with - the exports of livestock to the Arabian Gulf.

As Tame wrapped up the interview, thanking Peters for his time, Peters could be heard saying "Good lord".