WELLINGTON - NEW Zealand's opposition National Party is set to sweep Prime Minister Helen Clark from power after nine years in office, according to opinion polls a day ahead of Saturday's general election.

They showed the relatively inexperienced National leader John Key, who only joined parliament in 2002 after earning a fortune as an investment banker, on the brink of achieving his boyhood ambition of becoming prime minister.

The election campaign has focused on economic woes - the country has slid into recession and unemployment is at its highest level for nearly five years - and a more fundamental yearning for a change of government.

Mr Key, who was flying around the country in a frantic last-day campaign push on Friday, may fall short of the 50 per cent that his centre-right party needs to form a government on its own.

But with the help of two tiny conservative parties, he would be able to win a majority in the parliament of around 120 seats if voting follows the polls.

Since New Zealand's complex proportional voting system was introduced in 1996, no single party has been able to form a government without the help of minor parties.

A Fairfax Media survey released on Friday put National on 49 per cent support and Mrs Clark's centre-left Labour on 31 per cent.

A Herald-DigiPoll survey also released on Friday showed the gap was narrower, with National on 47.9 per cent and Labour on 36.4 per cent.

Two other polls released by television networks late on Thursday suggested National could form a government with the help of the ACT and United Future parties, which are predicted to win four seats between them.

Mr Key, who has led National since 2006, said the polls were 'fantastic', but added he was not taking the verdict of New Zealand's 2.9 million voters for granted.

'Polls are one thing, election night results can be a very different thing', he said.

Mrs Clark, for her part, insisted the polls meant little. 'That's what most of them said last time, there's nothing new about that,' she said.

At the last election Labour won 49 seats, only one more than National, and formed a government with the support of three minor parties.

Mr Clark spent her last day of campaigning in Auckland trying to ensure a high turnout in left-leaning areas of the city.

Respected as a strong if sometimes dour manager of the country during nine years of mostly solid economic growth, she continued to hammer her message that the untested Mr Key was not up to handling the fallout of the financial crisis.

'We're certainly picking up a lot of strong support for Labour out there on the ground, and the feeling that this isn't the time to jump into the unknown,' she said.

If Mrs Clark can defy opinion polls to win a fourth three-year term she would become Labour's longest serving prime minister, reflecting the stamina of the former Vietnam War protester who was nearly deposed as party leader in 1996.

However, the mood for change has been evident in polls for more than a year while the financial crisis looks set to deepen recession in a country of 4.3 million people that is heavily reliant on exports of agricultural commodities.

National and Labour are promising similar measures to keep the economy afloat, including tax cuts, infrastructure investment and extra support for people who lose their jobs.

Mr Key, a former Merrill Lynch executive with a fortune estimated at some NZ$50 million (S$43.3 million), says that his party offers 'the politics of aspiration over the politics of envy'. -- AFP