A Thai anti-government protest leader has been shot in the head while delivering a speech in Bangkok, as demonstrators blocked advance voting for a controversial general election.

Piya Utayo, a spokesman for Thailand's national police, on Sunday identified the dead man as Suthin Tharathin. "At least five other people were injured," he said. 

"Suthin Tharathin was shot in the head while giving a speech from the back of a truck," protest spokesman Akanat Promphan told AFP.

"The government has failed to provide any safety and security for anybody today despite the emergency decree," he said, referring to a government order empowering police to control protests.

Prime Minister Yingluck Shinawatra has called elections for February 2 in an attempt to defuse protests that have dragged on since November and which have flared occasionally into violence.

Polling stations attacked

Thai anti-government protesters besieged polling stations in Bangkok Sunday and forced most to close, hampering advance voting for next weekend's election and deepening doubts about whether it can go ahead.

More than two million people are registered for advance voting before the February 2 election, which was called by Prime Minister Yingluck Shinawatra to try to defuse rising political tensions after weeks of mass anti-government protests.

Protesters descended on scores of polling stations in the Thai capital and several southern provinces, stopping ballot officials from entering and prompting election authorities to shut at least 45 venues.

Their action denied the franchise to thousands of registered voters and flouted a government-imposed state of emergency invoked to ease fears of violence in the run-in to next Sunday's poll.

Source: Agencies