Mr Goh, who became prime minister in 1990, is expected to be replaced before the next scheduled election in 2006 by Lee Hsien Loong, deputy prime minister and central bank head who is also the son of Lee Kuan Yew, who ruled Singapore for the first 25 years after its independence in 1965.

With the long-ruling People's Action party (PAP) certain to hold on to power, attention will focus on the size of its parliamentary majority and of popular support in the midst of Singapore's worst recession since 1965.

The PAP gained 81 of 83 seats with 65 per cent of the votes in the last election in 1997, but a poorer showing this time would deprive the government of the strong mandate it is seeking to tackle economic problems.

The opposition's best showing was in 1991 when it won four seats with 39 per cent of the vote.

The four main opposition parties said they would contest only 29 of 84 seats when they submitted candidate lists on nomination day, which marks the start of the brief nine-day campaign.

It was the third election in a row that the opposition has contested less than half the seats.

The opposition parties have complained that redrawn election districts, the expansion of multi-seat wards, and the calling of a snap election last week place them at a disadvantage because they can not match the PAP's strong organisation. In addition, the government on Wednesday said it would raise the deposit amount for candidates by S$5000 (US$2740) to S$13,000, placing a further strain on the opposition's resources following a ruling that prohibits fund-raising through the internet and in public places.

The opposition is hoping to benefit from voter disenchantment about social inequality as the jobless rate is expected to rise to 4.5 per cent this year in a nation that lacks an unemployment insurance scheme.

Mr Goh admitted that Singapore is facing it worst crisis since independence, but said the PAP was best able to deal with economic dislocations and new security threats resulting from global terrorism.

The government announced a S$11.3bn stimulus package of tax cuts, infrastructure spending and cash handouts just a week before it called the election.