People's Party (PP) MP Parit Wacharasindhu said the government will be tested next month when parliament reconvenes to deliberate the entertainment complex draft bill on July 9.
Speaking at parliament on Tuesday, Mr Parit said the bill had been fast-tracked ahead of other crucial bills by coalition MPs who cited its urgency and importance.
He described the upcoming vote as a critical test for Prime Minister Paetongtarn Shinawatra's administration, given its slim majority.
Some coalition members, like the Prachachart Party, have already said they will reject the bill, and other MPs may also vote it down, he said.
Public trust in the government and especially Ms Paetongtarn has been shaken by recent events, said the opposition MP.
Mr Parit expressed disappointment at the government for failing to address key suggestions, including that it produce a comprehensive feasibility study, design a framework to counter gambling addiction and money laundering, and hold public forums to hear a diverse range of opinions before moving forward.
Mr Parit said there are several potential outcomes for this bill. The government could push it forward and face the same level of opposition, postpone its deliberation to buy time, or withdraw it to show the government is taking stock of all the objections.
"I don't know how long the current government will last, but I think what happens on July 9 will be a major test," said Mr Parit.
Meanwhile, party leader Natthaphong Ruengpanyawut urged the House speaker to begin the next parliamentary session on July 3, as stipulated by a royal decree issued on June 9, which is the day the entertainment complex draft bill is scheduled to be heard.
Thailand is facing a series of urgent domestic and international issues, including border tensions with Cambodia, a brewing conflict in the Middle East, high energy prices, contamination in the Kok River from Myanmar, and political and legal troubles involving both the government and the premier, he said.
