National leader Simon Bridges responded to the Prime Minister's speech by describing her leadership occupancy as "three years of dithering".

It was an all-out rumble in the House of Representatives - irresistible to Deputy Prime Minister and New Zealand First leader Winston Peters.

"It's like having a dual of wits with an unarmed opponent," Peters said, responding to Bridges' speech. "And I don't like being unfair to people - I'm a nice guy."

Peters made it clear there is no love lost between him and Bridges.

"You know it's rubbish and that's your specialty," he told the Opposition leader, and went on to describe him as a "sucker".

The Serious Fraud Office is currently weighing up whether to investigate if New Zealand First Party donations were being hidden through the New Zealand First Foundation.

ACT leader David Seymour didn't miss the opportunity to bring attention to it.

He held up three images in the House, the first image of a hexagon, the second of an octagon, and the third an image of Peters with the caption "should be gone".

"Let me give a bit of an education in some of the basic shapes: This is a hexagon, this is an octagon, and this is a should be gone - and there's so many reasons why he should be gone," Seymour said.

RNZ revealed more details on Wednesday of racing industry donations to the New Zealand First Foundation, from donors who thought they were giving to the party.

Peters is the Racing Minister.

Peters barged his way past journalists in Parliament, refusing to stop for questions, leaving the Prime Minister and his MPs to argue there was no quid pro quo, no favours for cash.

Ardern defended Peters, saying: "It is no secret to anyone that Mr Peters has a strong knowledge, understanding and longstanding connection to the racing industry."

She added, "No one policy is ever decided by one party - they go through all of us."

New Zealand First MP and Cabinet minister Shane Jones said he thought it was "just mischief-making to draw that connection".

Peters had just one thing to say as he fled past the media: "At 6.30 tonight on my Facebook your questions will be answered", referring to a tweet he sent Tuesday night.

"Within the next 48 hours, I will be letting you know the truth about the NZF Foundation. Answering questions live on Facebook. I will tell you what the latest hysterics are all about. Get your questions in now," the tweet said.