Some political parties and movements have vowed to push harder for either an amendment or rewrite of the 2017 constitution, saying only a fair charter will bring about a free and just election.
"Even after all those past charter-amending proposals ended up being shot down by the Senate, we remain committed to fighting for a new constitution that comes from the public," said Metha Matkhao, secretary-general of the Campaign for Popular Democracy (CPD), a pro-democracy and human rights group.
The CPD has been spearheading a campaign to rid the Senate of its ability to pick a premier by proposing to amend Section 272 of the constitution, which grants the Senate this power.
According to Mr Metha, the government is highly likely to dissolve the House after the Apec summit next month, which is why the CPD is stepping up its campaign.
Another campaign to drum up support for a public draft of the new constitution will run in parallel with this, he said.
Somchai Srisutthiyakorn, policy steering chairman of the Seri Ruam Thai Party, echoed similar sentiments about the likely dissolution of parliament.
Prime Minister Prayut Chan-o-cha's signal that ministries should come up with "New Year gifts" for the public suggests he plans to dissolve the House after December, said Mr Somchai, a former member of the Election Commission (EC).
Mr Somchai believed that was Gen Prayut's last-ditch attempt to woo voters before going down that path, in order to call for an early election.
The Thai Sang Thai Party (TSTP) and Democrat Party, meanwhile, voiced their support for a proposal to elect constitution drafters nationwide to rewrite the charter in a way that reflects the wishes of the public.
Along with the campaign for a new constitution-drafting assembly, the TSTP aims to gather 50,000 signatures for its charter-mending draft before it formal submits it to House Speaker Chuan Leekpai before the new parliamentary session begins next month, said Pokin Polakul, a former House speaker who is now the TSTP's strategic committee chief.
The Democrats support the move as always as long as the parts of the constitution about the monarchy are left untouched, said Chinnaworn Boonyakiat, a Democrat Party MP for Nakhon Si Thammarat who serves as a deputy chief government whip.