BANGKOK - THAILAND'S Election Commission opened an investigation on Monday into whether new Prime Minister Somchai Wongsawat should resign for violating the constitution, less than a month after a similar process ousted his predecessor.

'I have no worries at all,' Mr Somchai told reporters, adding that he had done nothing wrong and would defend himself in court if asked to.

The comments came shortly after the Election Commission said it would investigate whether Mr Somchai had violated the constitution by holding shares in Thailand's CS LoxInfo PCL, an Internet service provider that is a contract partner of CAT Telecom, a state-owned telecommunications service provider.

The constitution bars members of Parliament from holding shares in companies that do business with state enterprises.

If found guilty, Mr Somchai would be disqualified as a member of Parliament and therefore no longer be allowed to serve as prime minister.

Election Commission spokesman Ruangrote Jomsueb said a subcommittee would be appointed to investigate the matter and if it feels the case should be pursued will forward its findings to the Constitutional Court. He said subcommittee probe's generally take about 30 days.

The complaint was brought by Senator Ruangkrai Leekijwattana, who also filed the complaint to the Election Commission that brought down previous Prime Minister Samak Sundaravej.

'I want the Election Commission to investigate if the prime minister should be disqualified for violating the constitution,' he told reporters after submitting his petition.

His complaint centres on Mr Somchai's ownership of shares in Internet company CS Loxinfo , which has a long-termv contract with state telephone firm CAT Telecom to provide satellite Internet services.

The 2007 constitution, drawn up by the army after a 2006 coup against telecoms billionaire Thaksin Shinawatra, bars any elected politician from holding shares in a company that has a contract with a state firm.

Mr Somchai, who is also Thaksin's brother-in-law, brushed off the allegation.

'Before I took this job, I strictly followed every law,' he told reporters on Sunday after a hostile reception from an anti-government crowd at a Bangkok shopping mall.

Samak was ousted on Sept 9, when the Constitutional Court ruled he had violated the constitution by accepting pay to host TV cooking shows while in office.

The ruling came amid a tense political crisis in Thailand, with anti-government protesters occupying the prime minister's office compound calling for Mr Samak's resignation.

A few thousand protesters remain at the Government House, saying they are holding their ground to see if Mr Somchai meets their approval. -- AP, REUTERS