Thousands of Thai police are descending on various protest sites across the capital Bangkok to clear out camps and reclaim public space in a move dubbed "Operation Valentine".
Dozens of security personnel have been swiftly evicting the long-occupied protest venues and so far there are no reports of violence.
"Our police are ready to reclaim space and will try to avoid violence," said Paradorn Pattanathabutr, chief of the National Security Council.
At least 5,000 police personnel have been assigned for the operation to reclaim the state buildings from anti-government campaigners.
The areas surrounding Government House have also been restored and caretaker prime minister Yingluck Shinawatra and other officials are set to return to the besieged government headquarters after nearly two months.
Paradorn insisted the police will not use force against the demonstrators. He said: "You have to admit that people are suffering and there have been lots of complaints. I think police now have justification to enforce the law."
Local reports suggest the protesters, led by opposition leader Suthep Thaugusuban, are likely to resist the police move in certain pockets of Bangkok.
"We've prepared for the raid. We will remain at our protest site and take care of each other," said opposition leader Rawee Mashmadol.
On the eve of "Operation Valentine" four people, including a nine-year old boy and a monk, were shot dead by suspected Islamic rebels. The other two victims were women who were also set on fire.
Thailand's political tensions flared up late last year when the government proposed an amnesty bill that would have absolved former prime minister Thaksin Shinawatra of corruption charges and allowed him to return from exile.
The Thai opposition accused Yingluck of running a proxy government for her brother who was ousted in a military coup in 2006.
Yingluck withdrew the motion, announced the dissolution of parliament and fresh elections were held. But the opposition boycotted the vote, leaving only the ruling party in the field.
The results of the election, which are a foregone conclusion, are to be announced by the end of this month.