Police Minister Stuart Nash has shed some light on the confrontation at the parliamentary gym last week.

Trevor Mallard said security was called to quell the confrontation between Nash and another gym-goer.

Stuart Nash told Mike Hosking an argument over equipment was the cause of the dispute.

"I was working out on a particular machine and a guy came up to me and said he wanted to use it and I said, 'I'm still using it sorry, mate when I'm finished come along'."

"He insisted on using it and I said, 'no, mate'. He kept insisted and I finally lost my cool and said, 'there's something called gym etiquette, there is about five other machines you can use...come back when it's finished'."

"He kept insisting so I told him in no uncertain terms where I thought he could go."

Nash said he didn't know the person he had the dispute with.

He said he has been going to the gym for years and this is the first time he has had a problem.

"I've been going to a gym on and off for 25 years. I am a huge believer in gym etiquette and this is about how you conduct yourself in a gym."

"This is the first time that I have been so offended that I have actually raised my voice and given someone a serve."

The Minister admitted the situation was "pretty serious" but said he made sure he apologised.

"Afterwards, I apologised to the chap and said look I shouldn't have raised my voice like that, and I did genuinely apologise because I did lose my cool. But I was that offended for the first time in 25 years and I decided sometimes you have got to stand up for yourself."

National MP Mark Mitchell jumped to Nash's defence, saying the incident was "totally out of character".

"I thought what had happened is, he had caught his own reflection in the mirror and was just staunching himself out."

"The thing that I'm worried about is that, as captain of the parliamentary rugby team, and with you being one of our big impact players, whether or not we need to get you tested now for performance-enhancing drugs."

Stuart Nash said the gym is a much-needed sanctuary for him.

"MPs do go down there to work out and it should be our sanctuary, these sort of things shouldn't make the media."