Thousands of Thai protesters have massed outside four ministries, a major government office complex and more than a dozen provincial halls in an escalation of their efforts to oust Prime Minister Yingluck Shinawatra.

The Department of Special Investigation [DSI] was evacuated on Wednesday as about 2,000 protesters gathered outside, rallying against the prime minister and her influential brother, former premier Thaksin Shinawatra.

Hundreds of demonstrators also gathered in front of the ministries of labour, energy, health and commerce in Bangkok, along with local government offices in 19 provinces, according to a senior Interior Ministry official.

"We are very upbeat and I think we will win in a few days," protest leader and former deputy prime minister Suthep Thaugsuban told reporters, calling for the creation of an unelected administration to run the country.

"If we demolish the Thaksin regime... we will set up a people's council, which will come from people from every sector," he said. "Then we will let the people's council pick good people to be the prime minister and ministers."

Anti-government protesters chanted abuse at the DSI as scores of riot police scrambled to put on helmets and hold up shields, with crowds pushing against a low fence.

The DSI, located in a complex of key government offices, recently indicted Thaugsuban for his alleged role in the deaths of more than 90 people in a 2010 military crackdown targeting supporters of Thaksin Shinawatra.

Interest rate slashed

Thousands of demonstrators, angry at the continuing influence of Thaksin Shinawatra on his sister's government, have forced the closure of several ministries in the past two days, and they show no signs of letting up. 

About 3,000 protesters gathered on Wednesday at the Energy Ministry, 700 at the Commerce Ministry and 200 at the Industry Ministry, police said.

Interior Ministry Permanent Secretary Wiboon Sagnuanpong said all ministries were still operating.

As the turmoil swelled, Thailand's central bank unexpectedly cut interest rates Wednesday by 25 basis points, a move that extended the baht's loss by 0.3 percent to 32.08 against the dollar.

The bank also slashed the 2013 economic growth forecast to 3 percent, saying the political tension was affecting investor confidence.

Embattled Prime Minister Yingluck Shinawatra, who faces a no-confidence vote later this week, maintained that police would use their emergency powers to keep the peace.

"My government will not use force. This is not the 'Thaksin regime'; this is a democratically elected government," she told reporters.

Thaksin Shinawatra, a billionaire tycoon-turned-politician, is adored by many of the country's rural and urban working-class citizens, but reviled by many in the elite and middle classes, who accuse him of being corrupt and a threat to the monarchy.

Source: Agencies