The main opposition People's Party (PP) announced it would not take part in former protest leader Sondhi Limthongkul's planned anti-government protests, saying it would work within the parliamentary system to fulfill its role.
PP spokesman Parit Wacharasindhu said on Wednesday the party would focus on the government's work and address issues that were of public concern through parliamentary mechanisms.
These issues, including the justice administration process, the Khao Kradong land controversy and the 2001 memorandum of understanding on joint development in the Gulf of Thailand signed by Thailand and Cambodia, would be examined as usual, he said.
The party would also do it best to advocate for reforms and policies by submitting bills or proposing legal amendments, many of which were approved by parliament, he said.
Mr Parit was responding to comments by Nattawut Saikuar, an adviser to the prime minister, who said PP supporters might join the planned street protests.
The PP spokesman dismissed Mr Nattawut's comments as speculation, saying he had no idea on what it was based.
However, he insisted the party supports people's freedom of expression whether the party agrees with the issues and it hopes that political expression will not violate democratic principles.
"The party has no intention to whip up political movements outside parliament.
"We're determined to work within the system to keep the government in check and advocate for change," he said.
Mr Sondhi, former leader of the now-defunct People's Alliance for Democracy (PAD), caused a stir this week when he announced his plan to hold regular activities next year.
Some observers warned these activities could escalate into mass demonstrations against the Pheu Thai-led government and even lead to the seizure of power.
Mr Nattawut said previous demonstrations against the Thai Rak Thai-led government and the Pheu Thai administration culminated in the 2006 and 2014 coups.
PM's Office Minister Chousak Sirinil on Wednesday called on the public to consider the impacts of past yellow-shirt protests and the coups, saying they were important lessons for the country.
He said these incidents brought political instability which posed a major obstacle to the country's development.
Mr Chousak said there were no conditions which could trigger mass protests and added that no negotiations under the 2001 MoU were in progress.
He said the result of the talks would have to be reviewed and approved by parliament.
"Such a crisis is way behind us, and I don't want the country to go back to that point," he said.
The Pheu Thai Party member also brushed off speculation the Paetongtarn Shinawatra administration would be short-lived.
Paiboon Nititawan, secretary-general of the Palang Pracharath Party (PPRP), on Wednesday warned the government not to mess things up especially when dealing with charter amendments and the referendum bill, which are controversial matters.
He was commenting on Mr Chousak's remark that the waiting period for the referendum bill would be much shorter if it was classified as a finance-related law after the Senate last week won the joint House-Senate panel vote to retain the double majority rule needed to pass a charter amendment referendum.
The House is likely to affirm the simple majority when the bill is returned for a vote, as it has backed such a change in the past. In this case a 180-day mandatory "cooling-off period" would apply before the bill is passed.
However, if the bill is classified as a finance law, it will be suspended only 10 days, instead of 180 days.
Mr Paiboon said the government should respect the House regulations and the House Speaker's judgement that the referendum bill is not a finance bill.
He also said he agreed with some analysts' observations the Paetongtarn government might not last a year.