Members of both the coalition Bhumjaithai and opposition Democrat parties have spoken out against the government's entertainment complex bill, saying that the benefits will not outweigh the negative impacts.
Chaichanok Chidchob, the Bhumjaithai Party secretary-general, said after a meeting with the rest of the coalition on Tuesday that the party disagreed with the bill on four key points.
First, it would not resolve the issue of illegal gambling and may cause more gambling problems in both the new legal sector and the underground grey industry.
Second, the supposed benefits to state and public coffers do not justify the level of investment.
Third, using casinos to drive tourism is unnecessary given the pre-existing abundance of renowned attractions all over the country, said Mr Chaichanok.
Finally, he added, the bill fails to spell out exactly how Thai workers could secure the jobs.
In the meantime, Chaichana Detdecho, deputy secretary-general of the Democrat Party, called for the bill to be reconsidered and questioned whether Thailand could achieve the same growth as Macau or countries like Vietnam and Singapore following the change.
"The Democrat Party will not support this bill," said Mr Chaichana, adding that if the government really wants to boost national revenue, it could do so by legalising and taxing long-existing underground lotteries.
Suchatvee Suwansawat, deputy leader of the Democrat Party, expressed his concerns on his Facebook account following the coalition meeting on National Mother's Day, claiming gambling is a blight on family values.
He also questioned the possibility of drawing foreign tourists to Thai casinos when similar facilities are available in neighbouring countries.
As a result, he said, these casinos would eventually have to target Thais as customers.
Mr Suchatvee also pointed out the failures of integrated entertainment complexes in neighbouring countries, where promises of local jobs were not fulfilled, aside from a few hundred low-level workers. He said the link between casinos and severe crime, particularly money laundering, especially near the Thai border, has shown that such activities are difficult to control.
A source said the Entertainment Complex project, approved in principle by the cabinet back in April, hopes to give an added boost to the economy as Prime Minister Srettha Thavisin enters his second year in office.