Prime Minister John Key wants Mt Albert voters to consider what the Government is doing, rather than focus on local issues as his candidate Melissa Lee's campaign goes from bad to worse.

"Because you live in Mt Albert doesn't mean that you don't have a consideration for the big national issues," Mr Key told Radio New Zealand.

Ms Lee, a list MP standing in the June 13 by-election, yesterday apologised for saying a new motorway would divert South Auckland criminals away from the area, a remark that angered many who said she was stereotyping South Aucklanders.

She made the remark at a heated candidates' meeting on Wednesday night about a proposed motorway, which will require 365 houses in the electorate to be demolished. The Waterview extension is a massive issue in the by-election.

In Parliament yesterday Labour MP David Cunliffe said Ms Lee was: "worrying about brown people coming up your motorway and invading the good white suburbs of Mt Albert".

Mr Key said Ms Lee had fallen into a Labour trap at the meeting and needed to learn not to be provoked.

He told Radio New Zealand this morning that Mt Albert voters would consider the national perspective.

"I believe that they would look at a government that six months ago was elected on the back of wanting to make sure we had an economic future that was strong and prosperous, that lifted education standards, and made our community safer, and those things are the very things this government is implementing."

Mr Key has repeatedly said National was the underdog in the safe Labour seat but it still had a good chance.

Today he said it would be a herculean task to win Mt Albert, but it was not impossible.

Former Prime Minister Helen Clark retained Mt Albert at last year's general election with a majority of more than 10,000 but the party vote was much closer than that, with Labour beating National by 2426 votes.

Mr Key said he stood by his MP.

"In life people make mistakes, it's the fragility of mankind. It happens and it's the way it is.

"It's not the end of the world. She is, in my opinion, a very fine member of parliament.

"She's doing a good job, we're very proud of her, and we're not going to write her off simply because she makes one mistake."

The controversy was Ms Lee's second embarrassment for National this week - she is also fending off two allegations about her production company Asia Vision Ltd, which makes the Asia Down Under programme.

The first was that taxpayer money was used to make a promotional video made by her company for the National Party.

Ms Lee said the video was made using company equipment and staff who volunteered time, no NZ On Air funding was involved.

The second allegation was that Ms Lee had interfered in editing an Asia Down Under election special, which was a conflict of interest.

NZ on Air chief executive Jane Wrightson said Ms Lee had gone off screen and an independent producer had been brought in: "She had no editorial control".

She was looking into the allegations.

The company received $1.2 million from NZ on Air last year.

Green MP Russel Norman, who is also contesting Mt Albert, has asked the Electoral Commission to look at whether the video should have been declared as an expense.