KEY POINTS:
The election picture is becoming complicated, with a Herald-DigiPoll survey showing the gap between National and Labour narrowing - and the Greens and the Maori Party wielding influence over who will form the next government.
National retains a lead in the poll entering election year, registering 47.5 per cent support, down 3.8 per cent from its highest-ever Herald-DigiPoll rating of 51.3 per cent in November.
Labour is relatively steady on 38.7 per cent support, meaning the gap between the two major parties has fallen to 8.8 points from 13.2 points in November. But the big mover of the survey is the Green Party, which has rocketed to 9.1 per cent after looking in previous polls as if it might struggle to make the 5 per cent threshold.
Translated into seats in the House the Herald-DigiPoll survey paints a picture where National's potential to govern alone - a scenario seen in several polls at the end of last year - has evaporated.
Instead, National's hopes of forming a government would rest on a deal with the Maori Party or an unlikely coupling with the Greens.
On the poll results, New Zealand First would not return to Parliament unless leader Winston Peters can win an electorate seat.
DigiPoll chief executive Gabriel Dekel said the fluctuation in the Greens' fortunes in the past two polls may be due to the margin of error for smaller parties being significant, meaning swings could be marked.
He also speculated that at this time of the year people often spent time outside and might feel more in touch with the environment, while the Greens' association with an anti-whaling campaign may have had an impact.
The holiday period traditionally saw people feeling less resentful toward the sitting government and those who were associated with it, Dr Dekel said.
The poll was taken between January 10 and January 24, and it offers some relief for Labour after the party ended 2007 on the back foot.
Labour suffered a series of unwanted incidents involving ministers last year and bitter opposition to its Electoral Finance legislation.
Greens co-leader Jeanette Fitzsimons said "polls are polls", but the result was a lot better for her party than polls that came out late last year.
"I always felt that was a bit of an aberration, that we weren't really below 5 per cent three polls in a row, but 9.1 is the highest we've had for a long time," she said.
"One likes to think that it is just the result of a lot of hard work for a long time and the public are getting our message, and our issues are out there."
Ms Fitzsimons has been keen to emphasise that the Greens will be an independent voice in this year's election campaign and nobody's 'handbag'.
But it is clear in the DigiPoll survey that despite not wanting to look like an add-on to Labour, the Greens have supporters who very much prefer that it do a deal with Labour.
Of the people who said they would vote for the Greens in the poll, 80.4 per cent said they favoured Labour over National as a support partner.
The attraction is mutual, with 42.6 per cent of Labour voters saying they preferred their party working with the Greens rather than another smaller party.
Helen Clark remains the country's most preferred Prime Minister over National's John Key.
She enjoys 49.7 per cent support, 10.5 points ahead of Mr Key who is on 39.2 per cent.
The gap between the pair is slightly narrower than November's 12 points.
Mr Peters has slipped in the preferred Prime Minister stakes after enjoying a surge in November.
He is now on 3.8 per cent support, down from 8.1 per cent.
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