The trade union leader has threatened an indefinite general strike that could plunge the country into an even greater economic crisis. Thailand has already been badly affected by the ongoing domestic political crisis and the implosion of the global financial system.

Sawit has urged workers to back the actions taken by the People's Alliance for Democracy (PAD), a conservative group close to the monarchy and the military, which since the end of August has carried out a mass campaign against the government, including the occupation of the government district in Bangkok.

PAD has threatened to blockade parliament on Sunday with thousands of supporters ahead of a special session on Monday relating to next month's ASEAN summit to be hosted by Thailand in the northern city of Chiang Mai.

“We will evict all government officials from every state enterprise and every union will mobilise their members to join the protest on November 24 at 10:00 am onward,” read a statement by the State Enterprises Workers' Relations Confederation. “Every one of us will strike nationwide."

PAD’s demonstration at parliament building on Sunday is a response to a grenade attack on their Bangkok protest site on Thursday that killed one person and wounded 23. They blame it on the government.

The group has threatened further violence if Prime Minister Somchai Wongsawat does not resign. They accuse of being a puppet in the hands of his brother-in-law, former Prime Minister Thaksin Shinawatra, who is in exile after he was charged with corruption.

Thailand is on the verge of chaos and the situation could get worse. Thaksin has announced his participation in a rally organised by his sympathisers for 13 December.

Army and police are on a state of alert, ready to hold back demonstrations on 23 and 24 November. The use of force cannot be excluded.

A similar demonstration on 7 October ended with two dead and almost 500 injured.