Both candidates promised to rebuild lower Manhattan

The two candidates swapped insults during the campaign - Mr Bloomberg accused Mr Green of lacking business acumen, while Mr Green charged that Mr Bloomberg had little political experience.

The BBC's Malcolm Brabant in New York said there had been speculation that the black vote could swing the election in favour of Mr Green, because Mr Bloomberg had been accused of making a fortune in South Africa during apartheid and of belonging to whites-only clubs.

Mr Bloomberg's campaign was boosted by support from Mr Giuliani, who won acclaim for his leadership after the 11 September attack on the World Trade Center.

There was little to choose between the policies offered by the two rivals, our correspondent said.

Both wanted to rebuild Lower Manhattan and bolster New York's economy after the terrorist attacks.

They also agreed on continuing Mr Giuliani's campaign to make New York a safer city.

Mr Green has accused his rival of sexually harassing a former co-worker and trying to buy his way into City Hall - charges Mr Bloomberg describes as smear tactics.

Mr Green characterised his rival as an elitist dabbling in politics as a mid-life whim, pointing to his own credentials as a veteran Democrat and a publicly-appointed lawyer.

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Mr Bloomberg countered by accusing Mr Green of being disrespectful towards the city's Hispanic community.

Registered Democrats outnumber Republicans five to one in New York, but recent polls showed that as many as one in four Democrats planned to back Mr Bloomberg.