ACT Party leader David Seymour has called a fellow MP a "f***ing idiot" while speaking at a pre-election business conference in Wellington.
Mr Seymour was speaking during the minor party leader presentations at the Deloitte Business NZ conference at Te Papa when he hit out at New Zealand First's Richard Prosser.
Mr Prosser had spoken earlier at the conference, telling guests to sell their shares in Contact Energy because his party intended to return electricity assets to state ownership and control.
"That means if you have shares in Contact [Energy], get rid of them now," he said.
Mr Seymour said he was angered by Mr Prosser's position.
"The idea that you would have somebody who pretends to hold the balance of power - to come and tell you that a stock trading at $5.85 is going to be nationalised at $3.10 and you better all sell it," he said.
"Well, I realise in a role such as mine you are supposed to have a certain amount of decorum. But that makes me really angry - what a f***ing idiot."
Mr Seymour also attacked Mr Prosser's personal appearance, saying he was a man who could "barely manage his own diet and exercise regime" who could be managing a ministerial position after the election should NZ First be a Government coalition partner.
Mr Prosser, who returned to the event later for party leader Winston Peters' speech, did not hear the remarks.
During a Q&A after his presentation to the conference, Green Party leader James Shaw was asked how he was adjusting to his increased responsibility after the resignation of co-leader Metiria Turei.
He said while his workload had increased decision making had become more efficient and praised the rest of the party caucus for stepping up.
He also addressed the last Colmar-Brunton poll which put support for the party at 4 percent - below the threshold to return to Parliament.
Mr Shaw said it was the only one of five recent polls to record support that low, and noted it tended to run 2-3 percent behind others.