The Thai senator who helped bring down former premier Samak Sundaravej filed a similar complaint against his successor on Monday, accusing the new prime minister of violating the constitution.

Ruangkrai Leekijwattana has accused Thailand's prime minister of breaching the charter by holding shares in Internet provider CS Loxinfo. The Election Commission received the complaint Monday, a spokesman said.

"At present, there is no decision on whether the complaint will be further investigated or not. That decision must come from the five election commissioners," the EC's Ruangroat Jomsueb said.

"As a government office, we are mandated to accept every complaint submitted for further consideration," he added.

The current constitution, drafted while Thailand was under military rule, bans members of parliament from holding shares in companies with links to the state, and CS Loxinfo has a concession with government-owned CAT telecom.

Prime Minister Somchai Wongsawat, who was only elected earlier this month, said he was unfazed by the possible charges.

"There is nothing to worry about, let everything follow the legal process," he told reporters when asked about the complaint.

Sharp-tongued former premier Samak was stripped of office on September 9 after a court found that he had breached the constitution when he accepted payments for hosting two TV cooking shows. Ruangkrai filed the initial complaint against Samak in May.

Samak formed a government in February after his People Power Party (PPP) -- which ran on a platform loyal to ousted prime minister Thaksin Shinawatra -- won elections in December, the first since the September 2006 coup.

Court decisions, however, have plagued the party, with four senior PPP officials including Samak forced out of office by the courts.

The PPP itself is facing dissolution over claims that some of its members were involved in electoral fraud, threatening further political instability in a country that has been wracked by protests and turmoil since early 2006.

Somchai was elected as Samak's replacement on September 17, and his new cabinet was formally sworn in by the king last week.

One of its first challenges will be to end the occupation of the main government compound by the so-called People's Alliance for Democracy, which accuses the PPP of being too close to Thaksin and trying to amend the charter.