The protesters have camped out for two weeks outside Prime Minister Thaksin Shinawatra's princely offices in Bangkok's historic district, calling for him to resign over claims of corruption and abuse of power.

But with just days to go till snap elections on Sunday, protest organizers said they will move their sit-in Wednesday to Siam Paragon, the city's biggest and newest mall, located along one of the most congested streets in a city notorious for its traffic.

"If the protest stays there and blocks the road, traffic throughout the capital would be paralysed," traffic police chief Panu Kertlapphol told AFP.

The protesters say they will not stage their sit-in on private property but will camp in the street, which Panu said would be grounds to arrest them for blocking traffic.

"We would like take action against the protesters but the penalties (for traffic violations) are minimal and could lead to conflicts. So we will just let them face the public and social criticism, that will hurt them more," he said.

The protesters' decision to move downtown quickly soured the city's opinion of their drive to force Thaksin to resign, according to a poll released Tuesday.

Some 71 percent of 1,116 people surveyed Monday disagreed with the move, respected pollsters at Assumption University said.

The poll also found support for Thaksin rose sharply after the move was announced, while more people said they would vote on Sunday.

Nearly 65 percent of Bangkok residents said they planned to vote, up 24 points from a poll just two days earlier. And the number of people who said Thaksin should quit dropped to 26 points, down from 48 percent on Saturday.

"This could mean that as the protesters move, they are losing sympathisers," pollster Nopadol Kanikar said, adding that traffic concerns appeared to be behind much of the discontent.

Police said they will deploy at least 450 extra traffic officers in the area on Wednesday.

Thaksin, who was campaigning in his home town of Chiang Mai, said the government might take action against demonstrators if they cause serious disruption.

"We may use legal procedures to take action against protesters. But we will avoid using violence to control demonstrations," he told reporters.

The neighbourhood poses a special security concern because the protest at Siam Paragon will take place near the palace of Thailand's beloved Princess Maha Chakri Sirindhorn, and just one block from national police headquarters.

Chamlong Srimuang, one of the protest leaders, rejected the police worries.

"All of Bangkok is gridlock already. We won't be the cause of the traffic jam, the prime minister will. If he resigns, we will return home," he told reporters.

Owners of Siam Paragon and two adjacent malls decided to close at least for Wednesday and Thursday and will meet Thursday to decide when to reopen. The decision shutters a major component of downtown Bangkok's retail core.

Siam Paragon alone draws some 100,000 shoppers a day, 40 percent of them foreigners. The sprawling high-rise mall which fills most of a city block expects sales of 10 billion baht (256 million dollars) this year.

The opinion poll was a boost for Thaksin, who is hoping for a popular reaffirmation of his leadership in Sunday's election.

He called the election three years early in hopes of defusing the protest movement, but an opposition boycott and claims of fraud have already marred the vote.