Key Points:

National is privately hoping that allies Act and United Future might pull a combined 5 per cent of the party vote at the election, which could yet be enough to fire John Key into the ninth floor of the Beehive.

United Future leader Peter Dunne yesterday threw his party in behind National and ruled out working with Labour after the November 8 election.

This is despite Mr Dunne being a minister in the Labour-led Government and enjoying a ministerial car and salary until the election.

Mr Dunne met Mr Key in Wellington yesterday and when the pair emerged, the United Future leader said National's policies more closely aligned with his party's at a time when the economy was particularly important.

Asked if he would work again with Labour, Mr Dunne said United Future had "probably gone as far as we can in a number of key portfolio areas with them".

He pointed to the likelihood of the strong-polling Greens playing a big role in a potential Labour-led government and suggested that wouldn't work well with his party.

"Particularly some of the impediments that the likely involvement of the Greens would bring to that government make it difficult to see how we could advance the policies we are most interested in."

He categorically stated that United Future would not give its support to a Labour-led government.

The move comes after months of open flirtation with National by Mr Dunne, who has been Revenue Minister in Prime Minister Helen Clark's third-term Government.

He did not inform Helen Clark of his decision before yesterday's press conference, but she appeared to guess what was going on when she gave a media interview at a remote Northland location out of cellphone range.

"I'm not particularly troubled by what's been announced today," Helen Clark said.

"I hope we'll be in a strong position to form a government across a number of parties.

"It will have little effect on the election because Peter Dunne's party has very low levels of support - it may only return him as an MP."

In the latest Herald-DigiPoll survey United Future polled just 0.2 per cent support, but Mr Dunne appears likely to hold on to his Ohariu electorate seat and return to Parliament. He denied a suggestion he might have been in trouble in the seat.

National sources have indicated to the Herald some hope Mr Dunne could lift his party's vote in the final fortnight of the campaign, and together with Act poll a combined total of around 5 per cent. It could still turn out that National would need the Maori Party to govern, but it may not.

Progressives leader and Labour ally Jim Anderton called on Mr Dunne to give up his ministerial post now, as well as the car and other trimmings.

"It's not a good look to drive around in a ministerial car saying you want to get rid of the Government you are still part of," Mr Anderton said.

It is understood United Future went further than National expected it to when it decided to back Mr Key's party.

Mr Dunne's move has clinched a ministerial role for him in a National Cabinet if Mr Key becomes Prime Minister, although neither side was willing to speculate on potential portfolios.

It appears National is also campaigning predominantly for the party vote in the Ohariu seat, leaving open the likely return of Mr Dunne.

National list MP Katrina Shanks, who is contesting the seat, said she was campaigning for a change of government and that meant the party vote.

Asked what she would do if a person asked her whether they should vote for Mr Dunne, Ms Shanks said: "I'd say first and foremost, I'm after your party vote - if you want to give me the electorate tick, then I'd love to have that as well."

The latest One News/Colmar Brunton political poll last night put National on 47 per cent support and Labour on 35 per cent. The Greens were up to 8 per cent, New Zealand First was on 3 per cent, the Maori Party on 3 per cent, Act on 2 per cent and United Future on 0.4 per cent.

Meanwhile, Labour released its employment relations policy yesterday, promising to stand by workers during the economic crisis.