A protest calling for the resignation of Thai Prime Minister Samak Sundaravej and dissolution of his government entered its 100th day Monday, with thousands on demonstrators in command of Government House - the administrative seat.

The People's Alliance for Democracy (PAD), a loose coalition of conservative groups opposed to the current government, has been staging peaceful anti-government demonstrations on Rajdamnoen Avenue in the old section of Bangkok since May 25.

On Tuesday, in what the PAD dubbed "D-Day," the movement rallied more than 10,000 supporters who stormed Government House and seized the cabinet's working headquarters.

The protestors have occupied the seat of government for a week Monday, and show no signs of leaving.

Chamlong Srimuang, one PAD leader, described as "useless" a special joint session held Sunday by both houses of parliament to resolve the standoff.

Chamlong Monday rejected calls by the pro-government United Front of Democracy Against Dictatorship, another mob, to withdraw from the compound.

Efforts by police to forcibly oust the demonstrators from Government House on Friday failed.

The show of force drew immediate criticism from a broad swathe of Thai society, and prompted PAD supporters to raid and shut down three airports in southern Thailand. The three airports at Hat Yai, Krabi and Phuket all reopened Sunday.

The labour union at the state-run State Railways of Thailand (SRT) also went on strike as of Friday. As of Monday, the SRT was operating only 129 of its 244 trains.

The SRT board resigned en masse Monday, after the state enterprise reported a 60-million-baht (1.9-million-dollars) loss due to the partial strike.

Labour union leaders at the capital's state-run electricity and water utilities have threatened to shut down services should the government resort to violence in attempting to end the PAD protest at Government House.

Thai premier Samak is faced with a difficult dilemma: if he cracks down on the PAD, there will be a political backlash; but if he allows them to continue occupying his offices, he looks weak.

Political analysts said the Thai military is unlikely to assist Samak in getting rid of the PAD, which claims to be a staunchly monarchist movement devoted to cleaning up Thai politics.

The PAD was a significant movement two and a half years ago as the spearhead to topple former premier Thaksin Shinawatra, a billionaire populist politician who dominated Thai politics from 2001 to 2006.

Thaksin was overthrown by a military coup on September 19, 2006.

The PAD claims Samak is a stand-in for Thaksin, who is now living in self-exile in London.