BANGKOK - Anti-government protesters in Thailand, ignoring the snap election called by Prime Minister Yingluck Shinawatra, said she should be tried for treason and the whole of her influential family be hounded until they give up politics.

The protesters, a motley collection aligned with Bangkok's royalist elite, want to eradicate the influence of Yingluck's brother, former premier Thaksin Shinawatra, who was toppled by the military in 2006 and has chosen to live in exile rather than serve a jail term for abuse of power.

Thaksin is widely seen as the power behind Yingluck's government, sometimes holding meetings with the cabinet by webcam. He remains enormously popular in the countryside because of his and Yingluck's pro-poor policies and any party he is associated with stands a good chance of winning the election.

After forcing the snap election on Monday and massing 160,000 people around Yingluck's office, protest leader Suthep Thaugsuban had given her 24 hours to step down. She is caretaker prime minister until the February 2 election.

After that deadline ran out on Tuesday night, Suthep, who holds no office and resigned as a lawmaker to lead the protest movement, said police should arrest her.

"I ask police to arrest Yingluck for treason because she did not meet our orders," he told supporters still camping out at Government House.

Before the deadline had elapsed, he said: "If you don't listen, we will escalate our protest until you and the rest of the Shinawatra family are unable to stand it any more.

"How long will you be able to stand it if people spit on your car every day?" he said. In previous speeches he has said the whole Shinawatra family should leave the country.

Suthep says Yingluck's government had violated the constitution in several ways. In return, he has been charged with insurrection.

So far no attempt has been made to arrest him.

In his speech, Suthep urged the military, traditionally close to the royalists, to take control of government buildings in place of the police, who are closer to Thaksin, himself a former police officer.

Thai media reported that army chief Prayuth Chan-ocha had met Suthep at a military base but a spokesman for the protesters denied that.

"I have asked Mr Suthep and he said it's not true. It's a jumble of rumors and someone made it up," Akanat Promphan told Reuters on Wednesday.

The politically powerful army, which has staged or attempted 18 coups in the past 80 years, has said it does not want to get involved, although it has tried to mediate.

Protest leaders say they want to create a power vacuum in order to set up a "people's council". Suthep has said this council would be made up of appointed "good people".

Yingluck's Puea Thai Party enjoys widespread support in the populous north and northeast, Thailand's poorest regions. The party said she would again be its candidate for prime minister.

In contrast, the protesters are drawn from Bangkok's royalist upper and middle classes, including civil servants and prominent business families, along with people from the south where the opposition Democrat Party has long held sway.

The spark for this latest unrest was a government bid last month to force through an amnesty bill that would have expunged Thaksin's conviction, allowing him to return home a free man.

Protest leader Suthep's overriding aim is to get rid of what he calls the "Thaksin regime" - the family's influence on politics, plus the people placed in senior positions in state agencies and the police who are believed to answer to him.

In rambling speeches, he has claimed Thaksin and his family have hijacked power to serve their own interests, not the nation. Beyond that, his political programme remains sketchy.