Labour ministers will hit electorates throughout the country from Friday as a new poll shows their party falling behind a surging National.

During the House's four-week recess the MPs intend to seize the chance to work the electorates and convince their constituents to stay with them in an impending election.

Prime Minister Helen Clark says Labour clearly has work to do after last night's One News-Colmar Brunton poll showed its support waning and National racing ahead.

A spokesman said Labour would announce in the next few weeks new policies to take it into the election, which must be held by the end of September. He would not reveal what areas they would cover.

Last night's poll showed National's support rose 6 points on May's TVNZ poll to 43 per cent and Labour fell 3 to 41 per cent. NZ First was down 1 point to 7 per cent.

Support for National Party leader Don Brash as preferred prime minister rose 5 to 20 per cent. Helen Clark's was down 2 to 39 per cent.

The poll of 1000 voters is the second in three weeks to put National in front and indicates a close election. Like other polls, it also puts NZ First leader Winston Peters in the probable role of kingmaker.

An NBR-Phillips Fox poll on June 3 showed National overtaking Labour by 1 point, following other polls which showed the May 19 Budget had been poorly received.

The Budget has been widely regarded as a failure with the public, because it made only a minor adjustment to tax thresholds and these do not come into effect for three years.

Helen Clark said through a spokesman last night that it would be a close race but Labour was determined to win it. The Government had come under immense attack but despite that its support was holding up well.

He pointed out that at the last election Labour got 41 per cent - the same support as last night's poll.

Dr Brash said through a spokeswoman that it was pleasing to see voters turning to National's policies, including tax relief for "middle, mainstream New Zealand".

"Only National can change this Government and deliver these policies for middle New Zealand."

Mr Peters, who has dropped 5 points in the new poll's preferred prime minister stakes to 8 per cent, said the poll was worthless and he had nothing to say about it.

The Greens were down 1 to 3 per cent, meaning they would not return to Parliament. Act, with only 2 per cent support, would also not be back.

United Future would get just one MP back, assuming leader Peter Dunne kept his constituency seat.

Progressive leader Jim Anderton would probably win his seat again and support Labour. The Maori Party would have a handful of MPs.

But even if all these combined with Labour, they might still not give the centre-left a majority.

Thursday's 3 News-TNS poll put National on 36 per cent support, up 2 points on April, and Labour down 5 to 40 per cent.

On Saturday, a poll prepared for media group Fairfax by ACNielsen put Labour on 40 per cent and National on 38 per cent.

The One News survey had a margin of error of 3.2 per cent.

- additional reporting: Ainsley Thomson