Hundreds of protesters have occupied the camp since August, forcing the current government to base itself at temporary offices in Bangkok's old airport.

On Friday hundreds of supporters of anti-government People's Alliance for Democracy attended the funeral of the man, marching through the streets of the capital to the headquarters of the Thai police.

Anti-government protesters are threatening to step up action [GALLO/GETTY]
The PAD, a loose coalition of royalist businessmen and academics, has accused the government of having a hand in the attack, with one PAD leader urging supporters to bring down what he said was the current "murderous" administration.

Prime Minister Somchai Wongsawat has denied any responsibility in the attack.

A threatened strike, planned for Tuesday unless the government stands down, would likely cause huge disruption to Thailand's already shaky economy.

In August, a partial strike by the unions in support of the PAD caused havoc on the roads and railways, delaying shipments of commodities ranging from crude oil to rubber.

The strike call comes amid expectations the PAD will try to rally thousands of supporters to blockade parliament on Sunday ahead of a special session.

The last time PAD supporters rallied outside parliament, on October 7, two people were killed and hundreds injured in running battles with riot police.

The PAD accuses Somchai's government of being a puppet of Thaksin Shinawatra, the former prime minister who was ousted in a bloodless coup in September 2006.

The former leader is currently living in exile having skipped bail in a corruption case.