HONG KONG (AFP) - The Chinese gambling enclave of Macau heads to the polls on Sunday, with democrats expected to make little headway against pro-Beijing candidates riding a wave of support thanks to a booming economy and generous handouts.

The city of 590,000 has been transformed by the casino industry which is now the world's biggest, overtaking Las Vegas in revenues and employing some 23 percent of the total workforce.

The former Portuguese colony is holding its fourth legislative elections since it was handed over to Chinese rule in 1999, but since a surprise strong showing in the inaugural 2001 vote the democracy camp has struggled to attract support.

"This time the pan-democrats are facing an uphill battle," said Hong Kong Institute of Education Social Sciences department head Sonny Lo.

A strengthening pro-Beijing camp is providing stiff competition, along with special interest groups including candidates with casino backgrounds who are becoming increasingly popular and eyeing gains in Sunday's vote.

"They have lots of constituents, they have a lot of casino staff members and employees, and also the casinos play a crucial role in the economy and society of Macau," Mr Lo said.

Known for its tame political scene, the southern Chinese territory's leader is handpicked by a Beijing-backed committee, and only 14 seats in the 33-seat legislative body are selected through popular vote.

In 2009, when 60 percent of registered voters cast their ballots, democrats secured three seats in the legislature, with the rest of the seats shared by casino-affiliated candidates, business groups and pro-Beijing figures.

The campaign is a far cry from the vibrant democratic scenes in neighbouring Hong Kong, where millions can vote for a limited portion of the legislature and where outspoken pro-democracy forces enjoy strong support.

In Hong Kong, grassroots issues like soaring property prices and a widening income gap have fuelled resentment towards the government and calls for universal suffrage, but analysts say that in Macau the gambling riches have muted any dissent.

Since 2008 its leaders have been handing out annual cash payments to residents as part of a "wealth sharing" programme, with this year's worth 8,000 patacas (S$1,250).

As well as the handouts, the territory's unemployment rate is rock-bottom at 1.9 percent according to latest government data.

A record of 145 candidates are competing for the directly elected seats on Sunday, while a record of some 280,000 including many young first-timers are registered to cast their ballots.