Thai political protests spread outside the capital Wednesday as opposition demonstrators predicted a victory within days in their bid to overthrow Prime Minister Yingluck Shinawatra's crisis-hit government.

Raucous, whistle-blowing crowds have besieged government buildings to challenge Yingluck and her brother, ousted premier Thaksin Shinawatra, in the biggest protests since mass street rallies in 2010 that turned deadly.

The turmoil comes as Yingluck's embattled government faces a no-confidence motion in parliament introduced by the Democrats, who have not won an elected majority in parliament in about two decades.

While the demos have so far been largely peaceful, the fear is that they could descend into another bout of street violence in a country that has seen several episodes of political unrest since Thaksin was ousted in a 2006 coup.

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

Protest leader Suthep Thaugsuban urged protesters to march Wednesday on a large office complex on the northern outskirts of Bangkok that houses a number of government agencies, as the protests spread to several other provinces.

"We are very upbeat and I think we will win in a few days," the former deputy premier and key opposition figure told reporters as he left his de facto headquarters at the occupied finance ministry.

Suthep on Tuesday called for the creation of an unelected administration to run the country, in the clearest indication yet that the demonstrators are seeking to suspend the democratic system.

"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."

On Tuesday protesters surrounded the interior, agriculture, transport, and sports and tourism ministries, ordering officials inside to leave, a day after occupying the finance and foreign ministries.

A court has issued an arrest warrant for Suthep for his role in the seizures.

Demonstrators have also besieged several government offices in the opposition's southern stronghold, including on the island of Phuket, a top destination for foreign tourists, where several hundred protesters massed Wednesday outside a provincial hall.

The no-confidence debate is set to continue in the Thai parliament Wednesday and the ruling Puea Thai party, which holds a comfortable majority, is expected to win the censure vote expected later in the week.

The recent protests were sparked by Puea Thai plans to introduce an amnesty that could have allowed the return from self-imposed exile of Thaksin.

The Senate blocked the controversial bill but demonstrators have since broadened their goal and now want to bring down the government.

Yingluck on Monday ordered the expansion across Bangkok of the Internal Security Act, which gives authorities additional powers to block routes, impose a curfew, ban gatherings and carry out searches.

Her Red Shirt supporters, who have held their own rally at a sports stadium in the capital, appeared to be losing patience with the growing protests although they have refrained from taking to the streets in the latest standoff.

"The current situation is near breaking point," said Red Shirt leader Jatuporn Prompan, calling for more supporters to join their gathering.

But "we will only move out (on to the streets) if there's a coup," he added.