New York  - Billionaire Michael Bloomberg looks set to win an unprecedented third four-year term as New York mayor on Tuesday while setting an all-time spending record by a candidate using his own money.

He will have spent 140 million dollars by Election Day, while his opponent Comptroller William Thompson has so far spent a total of 6 million dollars, public records show.

Since September, Bloomberg has accelerated his campaign and spent to the tune of 1 million dollars a day, mostly in advertising on major TV networks, radio and websites.

Election records showed that Bloomberg also spent between 80 million and nearly 100 million dollars on each campaign in the two previous successful runs. Bloomberg's spending has been described as "obscene" by rivals.

Bloomberg's personal wealth is estimated at 16 billion dollars, fuelled by the namesake financial news service he founded from scratch decades ago after holding a job on Wall Street.

Bloomberg is considered an effective buttoned-down, no non-sense corporate leader who runs City Hall like a big firm. Some offices are adorned by two or three computer monitors on each desk, the same way Bloomberg financial news service reporters work.

If he wins a third term, which has been predicted because of his underfunded opponent's poor show, Bloomberg would have spent about 250 million dollars of his personal money in three campaigns - more of his personal wealth than any other US candidate for public office has ever spent.

New York media have kept a close watch over each of Bloomberg's moves and rarely found fault. When he asked the City Council to change laws increasing mayoral term limits from two to three, there was a muted outcry that did not last long.

Bloomberg was elected mayor in the wake of September 11, 2001 terrorist attacks that killed more than 2,700 people in the destroyed World Trade Center and inflicted tens of billions of dollars in damage to the city's infrastructure, Wall Street firms and jobs.

New Yorkers seem to feel comfortable having a successful businessman running the cosmopolitan of 8 million inhabitants as the city recovered from the trauma.

He succeeded Rudolph Giuliani, who emerged a hero from the September 11 attacks. Giuliani has been campaigning for Bloomberg's re-election.

Current New Jersey Governor Jon S Corzine, a former Goldman Sachs executive, had spent a reported total of 130 million dollars in two campaigns for governorship and an unsuccessful campaign for the US Senate.

Media magnate Steve Forbes spent 114 million dollars of his own money in two unsuccessful campaigns for the US presidency, while Texan Ross Perot spent 75 million dollars in two failed presidential bids. (dpa)