The first reading of the 2023 budget bill which kicks off on Tuesday will decide the fate of Prime Minister Prayut Chan-o-cha, as the Setthakij Thai Party and some micro parties are sending mixed signals as to whether they will stand by the coalition government.
If the 3.18-trillion-baht budget fails to clear its first reading, the prime minister will come under mounting pressure to resign. That said, the prime minister is more likely to dissolve the House if the bill is rejected.
As the opposition has vowed to reject the spending plan, Pheu Thai secretary-general Prasert Chanthararuangthong said the budget's fate will rest on the decision of Setthakij Thai and the micro parties.
The opposition has a combined vote of 206, while the coalition government has between 230-240.
Last week, Capt Thamanat Prompow, former Setthakij Thai secretary-general who is tipped to assume the party leadership, claimed he had the support of more than 40 MPs from various parties including the so-called Group of 16 and the ruling Palang Pracharath Party (PPRP).
Mr Prasert said it remains to be seen what these MPs will do, while insisting that there were no rebel MPs in the opposition who would break ranks.
However, Wanwichit Boonprong, a political science lecturer at Rangsit University, said the claim was an attempt to arouse public attention ahead of the planned censure debate.
"It's more like an exaggeration.... If they have 40 votes as claimed, they would have made made their move already. I don't think they have that many," he said.
The Setthakij Thai Party is scheduled to elect a new board next month, so derailing the budget, which will force drastic political changes, will only backfire on the party, he said.
Previously, Deputy Prime Minister Wissanu Krea-ngam said that if the budget is voted down in its first reading, the prime minister would likely dissolve the House rather than step down.
The government has little to worry about in the budget debate, Mr Wanwichit said.
"Capt Thamanat is likely to focus on undermining the prime minister until his term ends. The group isn't ready for the break-up [of the government]," he said.
His views were echoed by Jade Donavanik, former adviser to the Constitution Drafting Committee, who said the opposition has its sights set on the no-confidence motion.
The budget is the collective work of state agencies and state enterprises, not just the government, he said. If the bill is rejected, it will take about three months to come up with a new one, which would put the country's economic activity on hold, he said.
"Even if the opposition can topple the government through the budget vote, I don't think they will. There is no mechanism in place to support this scenario," he said.
When asked about the Setthakij Thai's stance, Capt Thamanat said on Monday the party places national interests before others and will propose changes to the budget when it is scrutinised by the House.
When pressed if this meant the party would vote for the bill, he said the party will meet ahead of the debate.
"I won't take part in the debate but the party's MPs will. I'll decide later if I will join the scrutiny panel," he said.
Peerawit Ruengluedollapak, a Thai Rak Tham Party list-MP and member of the Group of 16, said there are signs from Capt Thamanat that the budget bill should be accepted.
Pheu Thai and opposition leader Cholnan Srikaew said opposition parties agreed that they must reject it, instead of simply abstaining. He said the opposition will join the scrutiny process if the bill passes its first reading.