A joint sitting of MPs and senators on Thursday voted to pass Section 14 of the Royal Thai Police Bill, which deals with the composition of the Police Commission, at its second hearing.
Under this section, which was examined and revised by a parliamentary scrutiny committee, the prime minister would chair the commission.
However, the panel made changes to the body's structure by excluding the interior permanent secretary, justice permanent secretary, attorney general and secretary-general of the Court of Justice.
Under the original bill accepted at the first reading, all four were part of the commission.
Before the latest vote was cast, several MPs objected to the structure, saying it would open the door to political interference in the appointment of police.
Seri Ruam Thai Party leader Sereepisuth Temeeyaves said the prime minister, a political office-holder, should not be allowed to chair the commission, which oversees the Royal Thai Police.
He said past reshuffles of the police force were subject to meddling, and the principles of seniority, knowledge and merit ignored. The commission should be chaired by the national police chief or a former one, he added.
Many MPs also called for changes to the structure of the commission, proposing that the public sector as well as the chairman of the Lawyers Council of Thailand should be on board.
The meeting also passed Section 15 of the bill, which involves the duties and power of the commission. Under this section, the commission would be responsible for issuing rules and policy standards related to police officers.
Further readings were scheduled for Thursday and this Friday.