Thailand's embattled premier said Sunday she was willing to call an election to end mass anti-government protests as the kingdom's political crisis deepened with the mass resignation of opposition MPs.

Bangkok is bracing for another major anti-government demonstration on Monday, with protest leaders vowing a final showdown in efforts to topple Prime Minister Yingluck Shinawatra and curb the political influence of her brother Thaksin.

"We decided to quit as MPs to march with the people against the Thaksin regime," Democrat Party lawmaker Sirichok Sopha said.

The kingdom has been rocked by several episodes of political bloodshed since Thaksin, a billionaire tycoon-turned-premier, was ousted by royalist generals in a coup seven years ago.

Yingluck's government has been shaken by more than a month of rolling rallies by demonstrators, sometimes numbering in their tens of thousands, who want to suspend the country's democracy in favour of an unelected "People's Council".

Yingluck on Sunday renewed her offer of elections if the protesters -- a mix of royalists, middle class Thais and other Thaksin opponents -- agree to respect the democratic process.

"The government is ready to dissolve the house if the majority wants it," she said in a televised address, noting that under the kingdom's laws an election would have to be held within 60 days.

But "if protesters or a major political party do not accept that or do not accept the result of the election, it will just prolong the conflict," she said.

The protest leaders have said that they would not be satisfied with new elections, leaving the two sides locked in a stalemate that risks scaring off foreign investors and tourists.

"An unelected government would affect the country's reputation and stability," Yingluck warned. "If protesters want that, it should be asked whether it is the desire of the majority."

She also floated the idea of a referendum to solve the crisis but it was unclear what the nation would be asked to vote on.

Thailand's political conflict broadly pits a Bangkok-based middle class and royalist elite backed by the military against rural and working-class voters loyal to Thaksin.

The former premier went into exile in 2008 to avoid jail for a corruption conviction which he says was politically motivated.

Tensions remain high in the kingdom following several days of street clashes last week between police using tear gas, water cannon and rubber bullets against rock-throwing demonstrators.

The unrest has left five people dead and more than 200 injured in Bangkok.

Demonstrators and police have observed a temporary truce since Wednesday for the 86th birthday of King Bhumibol Adulyadej, who is treated as a near-deity by many Thais.

With turnout dwindling, protest leader Suthep Thaugsuban has called for a final push on Monday to bring down the government, describing it as "judgement day".

The former deputy premier, who now faces an arrest warrant for insurrection, has vowed to surrender to the authorities unless enough people join the march to the government headquarters.

But another leading figure in the anti-government movement, Satit Wongnongtauy, hinted on Sunday that the rallies could be prolonged.

"If we do not win tomorrow, we will not return home. We will bring victory home," he said.

New concrete barriers have been put in place around the seat of government ahead of the planned protest, but unlike previously security officials said barbed wire would not be used.

"The police will keep up negotiations and to try avoid any injury or death," said national police spokesman Piya Utayo, urging protesters to respect the law.

The government's own "Red Shirt" supporters plan their own rally on Tuesday in the ancient capital of Ayutthaya north of Bangkok.

The recent protests were triggered by an amnesty bill, since dropped by Yingluck's ruling party, which opponents feared would have cleared the way for her brother Thaksin's return.

They are the biggest and deadliest street demonstrations since 2010, when dozens of people were killed in a military crackdown on mass pro-Thaksin Red Shirt rallies in Bangkok.