Thai authorities might close polling booths if violence erupts during Sunday's disputed election which could further undermine the credibility of a vote that is deemed incapable of restoring stability in the polarised country.
The government has vowed to push ahead with the general election despite threats by anti-government protesters, camped out at major intersections in Bangkok, that they will disrupt the polls in an attempt to stop Prime Minister Yingluck Shinawatra's Puea Thai Party from returning to power.
The anti-government protesters took to the streets in November in the latest round of an eight-year conflict that pits Bangkok's middle class, southern Thais and the royalist establishment against the mostly poor, rural supporters of Yingluck and her brother, former premier Thaksin Shinawatra, who was ousted in 2006.
The main opposition Democrat party, which backs the anti-government protests, is boycotting the election, which Yingluck's party is bound to win but without enough members to achieve a quorum in parliament.
The prospect of polling stations having to close early because of trouble on the streets will only add to doubts about the vote's legitimacy.
Puchong Nutrawong, secretary-general of the Election Commission, said it was concentrating on security in Bangkok and the south, where the opposition is strong, after hundreds of thousands of people were prevented from casting their ballot during early voting last Sunday when protesters obstructed polling venues.
"We're focusing our security efforts in Bangkok and in the south. I've asked commission officials to call polling venues in southern Thailand today to ensure we are as prepared as we can be," Puchong told Reuters.
"If any polling station faces a security threat it can shut down."
The protesters say they want to rid the country of the Shinawatra family's political influence and accuse Yingluck, who swept to power in the last election in 2011, of being Thaksin's puppet.
The protesters say the self-exiled Thaksin is a corrupt crony capitalist who commandeered Thailand's fragile democracy, using taxpayers' money to buy votes with costly populist giveaways. Thaksin has been abroad since 2008 to avoid a jail term for graft.
He or his allies have won every election since 2001. His passionate supporters say he was the first Thai political leader to keep campaign promises to help the poor.
Fear of bloodshed
Protest leader Suthep Thaugsuban led a march in Bangkok on Friday, part of a three-day push to show opposition to the vote. He wants political reforms, including the setting up of a "people's council" of notable worthies, before another election is held.
More than 93,000 polling stations will be set up around the country on Sunday. The commission, which had wanted to postpone the vote because of the volatility, said it had authority to order troops and police to help ensure the election takes place.
"We don't want to use these powers because we don't want to see clashes that lead to bloodshed," said Puchong.
The protesters, members of the People's Democratic Reform Committee, forced polling stations in 49 of 50 districts in Bangkok to shut last weekend and voting could only go ahead in three of 15 southern provinces.
The government's decision to press ahead with the election has riled protesters and inflamed tension in Bangkok where demonstrators are in their third week of an occupation of several main intersections.
About 10,000 police would be responsible for security on Sunday and the army said it would increase its troops in the capital as back-up.
Ten people have died and at least 577 have been wounded in politically related violence since the end of November, according to the Erawan Medical Center, which monitors Bangkok hospitals.
The government imposed a state of emergency last week saying it wanted to prevent an escalation of the rallies but a protest leader sought a court ruling on the legality of the emergency and a civil court was expected to hand down a verdict on Friday.