Key Points:

Cabinet Minister Trevor Mallard has moved to put a bad year behind him -pleading guilty to fighting in a public place and apologising to whistleblower Erin Leigh.

Mallard has come under fire on both issues and today sought to cauterise further political damage ahead of the Christmas break.

He accepted the fighting charge at a status hearing at Wellington District Court.

Wellington accountant Graham McCready had brought a private assault prosecution against Mallard in relation to the altercation he had with National MP Tau Henare in October after Mr Henare taunted him in Parliament about his private life.

Mallard pleaded not guilty to an assault charge, but today pleaded guilty to the lesser fighting charge and agreed to pay $500 to the Salvation Army's Bridge drug and alcohol programme.

Shortly after the conclusion of the hearing, Mallard apologised in Parliament to Ms Leigh, who he had been accused of unfairly attacking under parliamentary privilege.

Ms Leigh quit as a public relations contractor at the ministry last year following the appointment of communications contractor and would-be Labour MP Clare Curran, who was recommended by Climate Change Minister David Parker.

Ms Leigh said the appointment amounted to political interference in what was supposed to be a neutral ministry.

Her statements spurred Mallard to describe her as a "sad" individual and an incompetent worker.

However she was subsequently praised by two of her former bosses and by the ministry's chief executive Hugh Logan.

Mallard has been under strong opposition pressure to apologise to Ms Leigh and today did so.

"On reflection I now believe it was not wise to make those comments. I apologise to her."

Mallard refused to comment on his apology, but was more forthright on his court case.

"I'm really pleased we've got it over with by Christmas. Clearly I shouldn't have been involved in the fight to start with. I was involved in the fight and the matter is now finished."

Mallard pointed out that the conviction under the Summary Proceedings Act was not criminal.

"The charge is one of a lower level - a non-imprisonable offence - and while I'm clearly not proud of it, it's in a different category to assault which I was certainly not guilty of."

Mallard said he was not happy with how the incident had reflected on the Government.

In return for the guilty plea to the lesser charge, Mr McCready withdrew an application to lay a second assault charge over an incident last year in which Mr Mallard was alleged to have clipped National MP Bob Clarkson around the ears with a manila folder.

Mr McCready told reporters he had achieved what he had set out to do - show that people were equal in front of the law and that ordinary people had a right to call politicians to account.

Mr McCready, who was without counsel at today's hearing, accepted a trial would have been a mess and said he was glad to get a compromise that achieved his aims.

Mallard refused to bag Mr McCready, but said he was pleased to have finished dealing with him.

"I think a number of us who are MPs have had people who are fairly hard to work with over a period of time and Mr McCready is in that category. He's not the worst and I think I'm pleased to have finished dealing with him."