A repentant Melissa Lee is battling to get her campaign for the Mt Albert byelection back on track after Prime Minister John Key was forced to intervene over comments she made at a public meeting.

Ms Lee - a National List MP and candidate in the Mt Albert election - apologised yesterday after saying at a public meeting on Wednesday night that the new Waterview motorway would channel South Auckland criminals past the electorate and reduce crime.

Her apology followed an initial refusal to resile from the comment on Newstalk ZB yesterday morning.

Mr Key was quick to step in, saying her comment was "stupid" but attributing it to her inexperience and the heat of the byelection campaign.

Ms Lee's written apology said she regretted her remarks and "was wrong to have implied that crime is solely a South Auckland problem or that the new motorway would reduce crime".

She refused to give media interviews but last night appeared on a candidates' debate on TVNZ's Close Up with fellow candidates, Labour's David Shearer and Greens co-leader Russel Norman.

She said she was not forced to apologise but had done so "after reflection".

She said the meeting was heated and emotional for those who had just found out their homes were under threat.

Asked how she could redeem herself, she said giving a fulsome apology "shows character". Ms Lee has also been in the news over claims that she used taxpayer-funded resources in a National campaign video clip made at her television production company.

Her company gets significant sums of NZ on Air funding to make the programme Asia Down Under.

Ms Lee has denied any funding was used for the video and said two staff had volunteered to help in their own time.

NZ On Air chairwoman Jane Wrightson said she had no concerns after a cursory check of the documents, but staff were still checking them thoroughly.

National is also facing a complaint to the Electoral Commission for not including the costs of the clip in its expenses return.

Mr Key said he did not regret having Ms Lee as the candidate, saying she was "a tremendous advocate for National".

Although she had slipped up, he did not believe she was a liability and she had a strong future as an MP.

"I won't hold it against her forever. She's a new member of Parliament and when people are new in those hotly contested campaign battles, sometimes they make mistakes."

But Ms Lee now has an uphill battle to win the June 13 byelection.

She was promoted by Mr Key last year as showing the new face of the party and he handpicked her to be the first of the new MPs to deliver her maiden speech.

On radio yesterday morning she had tried to explain the comment, maintaining that police told her motorways reduced opportunistic crimes, such as car theft, because criminals were less likely to be driving through suburban streets.

However, her opponents were quick to leap on the comment.

Labour leader Phil Goff said it raised serious questions about her judgment and Mr Key must now be ruing the choice.

Dr Norman, who said at the same public meeting that people should protest outside the Prime Minister's home, said it stereotyped people from South Auckland as criminals.

John Boscawen, the Act candidate, said it was inappropriate and he did not agree with her argument that it would reduce crime.