BANGKOK - Thailand's top court ordered Health Minister Chaiya Sasomsap to quit on Wednesday, the latest blow to the five-month-old government whose biggest coalition partner faces a threat of dissolution.

The ruling came a day after two verdicts against the six-party government that is already weakened by a prolonged street campaign which has unsettled investors and fuelled speculation of a snap election or even a coup.

The Constitutional Court upheld the findings by anti-graft investigators that Chaiya had violated the 2007 army-designed constitution by failing to disclose his wife's assets 30 days after he was sworn in as minister.

Chaiya, an ally of ousted Prime Minister Thaksin Shinawatra, currently on trial on corruption charges, said he accepted the ruling. His successor would be chosen by the People Power Party (PPP), which leads the coalition.

Prime Minister Samak Sundaravej was not available for comment, but he earlier shrugged off doubts about the stability of his government elected in December on a pro-Thaksin ticket.

"I am listening to all the criticism and will tell the people what I think on my Sunday TV show," Samak told reporters.

The opposition Democrat Party and several senators said they would file separate petitions soon to impeach the cabinet after a Thai court said the government's support for Cambodia's bid to list a 900-year-old temple as a World Heritage site was illegal.

Thaksin's opponents have whipped up a nationalist frenzy over the Preah Vihear temple, which many Thais believe belongs to Thailand, to try to kick out the Samak administration.

The PPP may face dissolution if a court concludes it was involved in vote buying by one of its deputy leaders, who was banned from politics for 5 years on Tuesday.

SNAP ELECTION?

The legal defeats have forced the government to focus on its political survival at a precarious time for the economy, as it faces soaring inflation and stuttering growth, analysts said.

The main stock index edged lower in afternoon trade as Thailand's army commander denied the latest coup rumours.

General Anupong Paochinda dismissed newspaper reports that the government may ask its army allies to launch a coup to tear up the 2007 military-designed constitution which has strengthened the courts' oversight of politicians.

"A coup won't be any good for the country," said Anupong, who took part in the putsch against Thaksin in 2006. "Political problems must be tackled through political means."

Despite his assurance, analysts said the long-term outlook for Thai shares was poor, with the index down more than 16 percent since a street campaign against Samak began on May 25.

"Although many stocks now look cheap, there should be further downside to the market as a whole," Thanachart strategist Pimpaka Nichgaroon said, predicting "more bad news is on the way".

She said there was a good chance Samak would dissolve parliament "within this quarter" to avoid the possible disbanding of his party.

A senior member of the PPP told a Bangkok radio show on Wednesday that a new party had already been formed and would welcome members of the PPP if it was disbanded.

Other analysts said a snap election was unlikely, but Samak might shuffle his cabinet to buy time. His enemies have vowed to keep up the pressure.

Leaders of the People's Alliance for Democracy (PAD), whose 2005 street campaign led to Thaksin's ouster, cheered the court verdicts and vowed to continue their rallies until Samak quit