Voting closed in New Zealand's general election on Saturday, with polls suggesting the centre-right National Party, led by John Key, will sweep back into power with an increased majority.

Key has promised to build on policies of the past three years with an emphasis on sparking economic growth by cutting debt, curbing spending, selling state assets and returning to a budget surplus by 2014/15.

The most important thing is getting the economy right, said salesman Kelly Weaver, 25, after voting. He said he did not want to leave New Zealand to look for work in neighbouring Australia, as around 34,000 New Zealanders have done in the past year.

Election officials reported a strong turnout in many areas as fine weather brought out voters. More than 320,000 votes were cast in advance, up around 20 percent on the 2008 election.

Key voted at a school near his Auckland home and said he was taking nothing for granted despite the party's commanding poll lead.

You feel a combination of excitement and a little bit of nervousness and anticipation, Key, casually dressed in a blue open-collar shirt, jeans and white trainers, told reporters.

He visited party workers and then returned home, where he will watch results come in before going to the National party's rally in the ballroom of Auckland's casino.

Opinion polls published in the last day of the campaign put Key's centre-right National Party as many as 25 percentage points ahead of the Labour Party.

Labour leader Phil Goff held on to hopes that his party would stage a late recovery and escape a drubbing. He said he was feeling good about the strong campaign he had waged but it was all up to the voters.

Exit polls are not allowed in New Zealand, but if the surveys before the election are mirrored in the vote, National may gain an outright majority, the first time since the country switched to a proportional voting system in 1996.

Parties must secure either a local electorate seat, or five percent of the nationwide vote, to enter the 120-seat parliament.

Two small parties, the free market ACT and centrist United Future, which supported the outgoing National government, are both struggling for survival and if they fail to get back in parliament, National may be forced to look to the Maori Party.

That party, which represents New Zealand's indigenous Maori people who make up 15 percent of the population, backed National after the last election and said it could do so again.

Labour's chances of forming a government look negligible, and the polls suggest it will lose seats. It campaigned strongly on no asset sales, but has been unable to dent the ratings of the affable Key, a former foreign exchange dealer.

But Kiwis also go on personality, said John Parenga, 20, a cafe worker, who cast an advance vote for National.

Next to Auckland's town hall, an eclectic group of protesters set up what they called the Occupy Auckland camp, promoting a mix of causes. Anti-capitalist slogans were posted on a wall at the edge of the camp, including John Key = Wall Street.

There are about 3 million registered voters, out of a population of about 4.4 million. Voting is not compulsory.

Results were expected around 11 p.m. (1000 GMT).

(Reporting by Ed Davies; Writing by Gyles Beckford; Editing by Ron Popeski)