SINGAPORE (AFP) -- Singaporeans go to the polls today with the ruling People's Action Party (PAP) widely expected to win another crushing victory despite the strongest opposition challenge in almost two decades.

The healthy economy is expected to work in favor of Prime Minister Lee Hsien Loong's party, which is credited with turning multi-racial Singapore into a wealthy and stable society and has never lost an election since 1959.

But critics say a growing income divide, the plight of the elderly and less-skilled workers and a desire by younger voters for a less authoritarian system could help the opposition spring a few surprises.

The PAP held all but two of the 84 seats in the last Parliament. The opposition is contesting 47 seats, more than any election since 1988, but is the first to admit it cannot win a majority.

With 37 seats already won by the PAP without a fight, some 1.2 million voters will cast ballots for contested seats from 8:00 A.M. to 8:00 P.M. (0000 to 1200 GMT) in 422 stations. Results are expected by Sunday.

With a PAP majority already assured, the polls will serve as a referendum on the prime minister's performance.

Lee, the 54-year-old son of Singapore's independence leader Lee Kuan Yew, 82, is seeking his own mandate after inheriting the job almost two years ago when Goh Chok Tong, 64, stepped down as part of a pre-arranged succession. "I am asking for a personal mandate to work with you, to take you into the future and move forward together," Lee told a news conference Thursday. "Show us your support and give us a strong mandate."

Apart from the number of seats won, the focus will also be on the percentage of the popular vote for the PAP.

Comparisons will be made with the 75 percent mandate the PAP got in the 2001 elections under Lee's predecessor Goh.

In the current campaign, the PAP has used its classic strategy of attacking key opposition personalities while tackling "bread and butter" issues like upgrades of public housing estates, where most Singaporeans live.

"This election is an extremely important one in the sense that there are so many factors that are unknown," said political commentator Seah Chiang Nee. "One can sense a new political wind blowing across the land. People are starting to question whether it's a good idea to have such a strong one-party rule without proper checks and balances."

Three opposition parties -- the Workers' Party, Singapore Democratic Alliance and Singapore Democratic Party -- are putting up a robust fight but are hamstrung by limited access to the media, bans on Internet electioneering, defamation suits filed by PAP leaders and other problems.

One of the positive factors for the government is the economy.

After growing 6.4 percent in 2005, it expanded 9.1 percent in the first quarter from a year ago. Unemployment and inflation are well below western levels, the Singapore dollar is strong and the stock market is at record highs.

The government -- which denies buying votes -- has also released cash grants ranging from 200 to 2,600 Singapore dollars (127-1,656 US) to adult citizens as their share of fiscal surpluses resulting from economic growth.

However, opposition rallies have been attracting huge crowds despite strict campaign guidelines. Their candidates are urging voters to accept the cash grants as "your money" but elect people who can serve as checks on the PAP.

Younger, better educated and well-traveled Singaporeans have also become more outspoken. In one televised pre-election forum, a panel of young Singaporeans hurled blunt questions at founding father Lee Kuan Yew. "Many young Singaporeans know what they want and the PAP is not getting the signals," businesswoman Tan Keh Huier, 25, told AFP. "We want to see a 'speaking up' parliament rather than one that is dominated by one party." But university student Kok Tse Wei, also 25, said he would vote for the PAP, arguing that all the complaints against the ruling party have not "outweighed the comfort of living here."