Thailand's governing political party chose the brother-in-law of ousted former leader Thaksin Shinawatra on Monday as its nominee to become the next prime minister, plunging the country into further political uncertainty after weeks of protests and rumours of impending military coups.

Somchai Wongsawat, 61, became acting prime minister last week when Samak Sundaravej  — dismissed by protesters as a stand-in for Thaksin — was found to have violated the constitution and ordered to resign after seven months in office.

Parliament is scheduled to vote Wednesday on the nomination of Somchai as Samak's permanent replacement, but the appointment was far from assured after dozens of members of the ruling People's Power Party said they would not vote for him.

The announcement of the nomination by executive members of the ruling party was swiftly rejected by protesters who have occupied the prime minister's official compound for three weeks, insisting that  they will not allow another ally of Thaksin to take office.

"Somchai is very close to the Shinawatra family," said Chamlong Srimuanng, one of the protest leaders. "He is Thaksin's brother-in-law and will be even more his proxy than Samak ever was."

Thaksin, who recently fled to London to escape corruption and abuse of power charges, was deposed as prime minister in a 2006 military coup but remains the central figure in Thailand's long-running political crisis.

Thai poor still like Thaksin

The People's Alliance for Democracy, which has led the anti-government campaign, was formed in early 2006 to oppose Thaksin, a telecommunications tycoon and one of Thailand’s richest men.

He remains very popular among his country’s rural poor, but the urban elite and middle classes, backed by the Thai army and some members of the royal family, form the core of those opposed to him.

Samak, a close Thaksin ally, was elected by a wide majority in December but was quickly dismissed by the People's Alliance for Democracy as a proxy for Thaksin. Anti-Samak street protests began in May and gained momentum when the alliance stormed the prime minister’s official residence last month.

Army generals refused to enforce a state of emergency imposed by Samak.

Despite its booming economy and hugely successful tourist industry, Thailand has been plagued by political instability for much of the past 60 years.

There have been at least 18 military coups and attempted coups since the country moved from authoritarian to constitutional monarchy in 1932.

With files from the Associated Press