BANGKOK - Thailand's ruling party struggled to agree on a new prime minister Monday as one key faction walked out of talks, adding to the political uncertainty as the government faces down weeks of protests.

Dozens of parliamentarians from the People Power Party (PPP) walked out of a meeting in the Thai capital where party executives proposed acting premier Somchai Wongsawat to permanently take over the job.

"The candidate who is supported by the PPP executive may create conflict and confrontation, which will affect democracy," parliamentarian Boonjong Wongtrairat told reporters after walking out.

Somchai, 61, is married to the sister of deposed premier Thaksin Shinawatra and his selection would likely inflame anti-government protesters, led by the People's Alliance for Democracy, who seized the prime minister's offices last month.

The mild-mannered Somchai has also worked as a judge and brings over two decades of experience as a senior bureaucrat to the position, having held the highest ranking positions at Thailand's justice and labour ministries.

The PPP was forced to pick a successor to Samak Sundaravej after his bid to return to power last week, three days after being stripped of office, was torpedoed by a party revolt.

Party spokesman Kudeb Saikrajang said the executive committee had backed Somchai. After the walk-out, the leadership might be forced to consider two other possible candidates - a deputy party leader Sompong Amornviwat, and party secretary-general Surapong Suebwonglee.

Parliament is scheduled to vote on the prime minister on Wednesday. "Somchai is going to be a sitting duck if he takes over the premiership as expected Wednesday, because the PAD will attack his fatal weakness as being
Thaksin's brother-in-law," said political analyst Thitinan Pongsudhirak.

But any of the candidates would struggle to end Thailand's political chaos, as the thousands of protesters besieging the grounds of Government House since last month have declared they will stay as long as the PPP is in charge.

"We insist that we will not accept anyone from People Power Party to become prime minister," one protest leader, Pibhop Dhongchai, told AFP.

The demonstrators stormed Government House nearly three weeks ago to try to force the resignation of Samak and his cabinet.

Last week the Constitutional Court stripped him of office, ruling that he had illegally accepted payments for hosting television cooking shows. Samak then Friday ended his bid to return to power after being deserted by his allies, scuppering a re-election vote in parliament.

The demonstrators, who represent Thailand?s traditional elite, claim Samak and the three candidates to replace him are proxies for Thaksin. The PAD also spearheaded protests against Thaksin in 2006, leading to the military coup that toppled him.

They are also pushing a broader agenda to scale back democracy by reducing the influence of poor, rural voters, who gave Thaksin their steadfast support for providing universal health care and low-interest loans. Thaksin now lives in exile in Britain to evade corruption charges, which he says are politically motivated.

Despite that he casts a long shadow over Thai politics. His supporters won last December's election and he was consulted about Samak's renomination last week.

Meanwhile the Supreme Court is set to rule Wednesday in a corruption case against Thaksin and his wife. That verdict is expected shortly after the vote in parliament for the new prime minister.