Wellington - New Zealand's conservative National Party swept into power on Saturday in a general election that saw an overwhelming vote for change after nine years of rule by Prime Minister Helen Clark's Labour-led coalition.

Clark, 58, the first Labour leader to win three elections, immediately announced that she would step down from the party's leadership before Christmas, although she will remain in parliament having retained her Auckland seat.

She congratulated the National Party's leader John Key but, noting Labour's achievements since winning power in 1999, she said, "I do hope that all we have worked to put in place does not go up in flames on a bonfire created by the right wing of politics."

Key, 47, is a former foreign currency dealer and the richest man in the House of Representatives. He will be joined in a centre-right coalition by the free market ACT party who gained three seats to add to the Nationals' additional 11 in a 7 per cent swing against Labour.

Referring to the international financial crisis, Key pleaded for unity as he pledged to work to create a more prosperous New Zealand, but warned the country, "The road ahead may well be a rocky one."

He promised to lead a government "that serves the interests of all New Zealanders" and announced that he would hold talks on co-operation with the Maori Party, which was on course to win at least five of the seven seats reserved for the indigenous people.

With the final count still to be confirmed, Television New Zealand predicted the Nationals and their allies would have 65 seats in the new parliament of 122, against 52 for Labour and their Green coalition partners.

With support of the five Maoris, Key would have a solid majority in parliament.

The Nationals took 45 per cent of the crucial party vote and Labour 33 per cent.

The Greens - the only minor party to top the 5 per cent needed to guarantee a place in parliament - gained two seats and will have eight members in the new parliament, not enough to help Labour form a new centre-left government.

New Zealanders have two votes - one for their local constituency member of parliament and the other for a party. The party vote is the most important in deciding the government.

A high profile casualty of the election was Winston Peters, leader of the nationalist New Zealand First party and former foreign minister in Labour Prime Minister Helen Clark's minority government.

Peters was beaten by a National Party newcomer in his traditional seat of Tauranga and his party failed to reach the 5 per cent of the vote needed to remain in the House of Representatives.

Subject to confirmation, the parliament will comprise: National 59, ACT 5, United Future 1. Labour 43, Green 8, Progressive 1. (dpa)