BANGKOK (Reuters) - Thailand's government will deploy 10,000 police in the capital for Sunday's election, which protesters have promised to disrupt as part of their drawn-out attempt to topple Prime Minister Yingluck Shinawatra.

The government decided on Tuesday to press ahead with the Feb 2 election, which the main opposition party plans to boycott and despite warnings that it could lead to more violence without resolving the country's increasingly bitter political divide.

"I ask Bangkok residents to come out and vote," Labour Minister Chalerm Yoobamrung told reporters on Wednesday.

"The police will take care of security... Those who are thinking of going and shutting polling stations in the morning should think twice because the police will not allow them to."

Protesters prevented early voting at many polling stations in Bangkok on Sunday.

They took to the streets in November in the latest eruption of a political conflict that has gripped Thailand for eight years. It broadly pits Bangkok's middle class and royalist establishment against the mainly poor, rural supporters of Ms Yingluck and her brother, ousted former premier Thaksin Shinawatra, who lives in self-imposed exile.

The protesters accuse Ms Yingluck of being a puppet of Thaksin, a man they say is a corrupt crony capitalist who used taxpayers'money to buy elections with costly populist giveaways.

Mr Chalerm, who is in charge of a state of emergency imposed last week, told reporters about 10,000 police would be dispatched on Sunday to take care of security at the capital's polling stations.

Even though Ms Yingluck's ruling party is certain to win, not enough candidates have been able to register to provide a quorum in the new Parliament after the election.

By-elections will have to be held later to fill the vacant seats, which means the prospect of a caretaker, and fairly powerless, government under Ms Yingluck for several more months.

The protests are taking their toll on the economy and even major foreign investors are beginning to question the merits of ploughing any more money into their Thai operations.

Protesters took to the streets of Bangkok again on Wednesday but in a relatively small rally of about 500 people.

They were without their firebrand leader Suthep Thaugsuban, who was apparently deterred by the previous day's violence in which a protester was shot and wounded.

In a sign of how the legal establishment has largely lined up against Ms Yingluck's government, a criminal court on Tuesday rejected a government application for an arrest warrant against Suthep, saying there was not enough evidence to grant it.

Suthep is already wanted for insurrection and on charges of murder related to violence in 2010 when, as deputy prime minister, he sent in troops to crush protests by "red shirt" supporters of Thaksin. The death toll then was more than 90.

Thaksin, with his huge wealth and support, is deemed a threat to the Bangkok-based establishment, dominated by the military and the bureaucracy, and Suthep and his followers want to eradicate the influence of the former telecoms tycoon and his family by altering electoral arrangements.

The Election Commission, also widely seen as favouring the establishment-aligned opposition, had been arguing for a delay in the vote of up to four months, saying the country was too unstable to hold an election.

There are widespread fears that violence could escalate.

So far, the military has stayed firmly on the sidelines, in contrast to the past: It has staged or attempted 18 coups in 80 years of on-off democracy.

Analysts say the army is nervous that this time intervention would trigger even more violence with Thaksin's "red shirt" supporters threatening to descend on the capital if Ms Yingluck is overthrown.

Ms Yingluck is Thailand's fifth prime minister since the populist Thaksin was toppled by the army in 2006 and went into exile two years later to escape a jail sentence that was handed down for abuse of power.