BANGKOK - THAILAND'S prime minister is due in court on Monday as his party tries to fend off a possible ban that threatens to further shake the kingdom's fractured political landscape.

Abhisit Vejjajiva, alongside other executives, faces a five-year ban from politics and the ruling Democrat Party could be dissolved if it is found guilty of corruption by the Constitutional Court.

The premier is set to be a witness for the defence in what could be the final hearing before judges rule on the case, which centres on claims of misuse of a 29-million-baht (S$1.3 million) state grant in 2005. 'We are satisfied with the facts we have presented to the court and confident our party has done nothing wrong,' Democrat lawyer Virat Kalayasiri told AFP.

The party faces accusations that it paid 23 million baht to advertising firms, despite only having permission to spend 19 million on billboard marketing.

Thailand's Election Commission (EC) in April called for the party to be abolished over the claims as well as a separate case alleging an undeclared political donation. Judicial rulings have played a pivotal role in shaping the kingdom's politics in the past.

The Democrats, Thailand's oldest party, came to power two years ago after controversial court decisions ousted allies of fugitive ex-premier Thaksin Shinawatra, who was dislodged in a 2006 military coup. Two premiers were deposed from office by the judiciary in 2008 - one of whom, Samak Sundaravej, was removed for taking payments for hosting TV cooking shows.

Thai PM to face court