Bhumjaithai Party leader and Public Health Minister Anutin Charnvirakul said the House rejected his party's "well prepared" cannabis bill for purely political reasons ahead of the coming general election.
He was delivering a speech on "Health for Wealth" at the annual academic conference of the Public Health Ministry in Songkhla province.
The public health minister said cannabis was a cash crop in addition to having medical merits, and then referred to Wednesday night's rejection by the House of cannabis legislation introduced by his Bhumjaithai Party.
"Yesterday in the House an unseemly incident occurred. The Cannabis and Hemp Bill, which had already been improved by a House committee, was withdrawn from deliberation and those who proposed and supported the removal claimed that they wanted careful consideration of it," Mr Anutin, also a deputy prime minister, said.
Mr Anutin said the bill was earlier approved in principle and a House committee and its experienced advisers in all relevant fields improved it by making changes to 21 of 45 original sections, and adding more than 60 new sections.
"I wonder why the revised bill... is not better prepared than the original draft. It is quite clear that the issue has been politicised," he said.
"With many people starting to benefit from the cannabis policy and the election approaching, it is understandable that opponent groups act with political purpose," Mr Anutin said.
Before the last general election, his Bhumjaithai Party had promised to decriminalise cannabis for medical and economic reasons.
Despite the bill's rejection by the House, Mr Anutin said people would continue to receive the medical benefits of cannabis, because the Public Health Ministry had already issued and applied the necessary regulations for this purpose when cannabis was decriminalised.
Before the House voted on the bill on Wednesday, the coalition Democrat Party and the opposition-core Pheu Thai Party said cannabis should be relisted as a narcotic, expressing concern about its possible widespread abuse if households were allowed to grow it.
Bhumjaithai has been insistent that campaigns for the proper use of cannabis could prevent its abuse.
On Wednesday the House rejected the cannabis bill by 198 votes to 136, with 12 abstentions.
The MPs who supported its withdrawal were from many political parties - Pheu Thai, Democrat, coalition-core Palang Pracharath, Chartthaipattana, Seri Ruam Thai and Prachachat.
Ninety-three Pheu Thai MPs voted against the bill, while seven of their colleagues wanted to keep it. Those seven politicians reportedly plan to join Bhumjaithai.
