ANTI-GOVERNMENT protesters forced their way into Thailand's Finance Ministry yesterday, laying out sleeping mats in its rooms and hallways as attempts to overthrow Prime Minister Yingluck Shinawatra escalated.

Demonstrators also broke into the compound of the Foreign Ministry.

The seizing of government buildings by protesters led by the opposition Democrat Party thrusts Thailand into a new chapter of political volatility three years after it was rocked by its bloodiest political unrest in a generation.

The protesters say Ms Yingluck is a puppet of her brother, former prime minister Thaksin Shinawatra, who was ousted in a 2006 ministry coup and convicted two years later of fraud - charges he denies. Thaksin lives in self-imposed exile but exerts enormous influence over his sister's government.

Around 1000 protesters swarmed into the Finance Ministry's compound yesterday, filling the first floor and occupying six others. Many gathered in hallways and meeting rooms, blowing whistles and spreading out mats for sleeping and eating.

Staff left the building and moved to a car park.

Protest leader Suthep Thaugsuban told a crowd in front of the ministry: "Our only objective is to rid the country of the Thaksin regime."

Ms Yingluck said the protests risked harming investor confidence in Thailand and the nation's tourism industry.