Order No.115/2557 announced on July 21 transfers the prerogative of provincial governors in filing or not filing criminal lawsuits to commissioners of provincial police.
Kanit na Nakorn, chairman of the Law Reform Commission of Thailand and a former attorney general, told Isra News on Wednesday the amendment disrupted the long-established checks and balances in the judicial process.
"The amendment is not a check but rather a power grab. Up until now, a public prosecutor filed lawsuits and the court checks them. The existing check is already good," he said.
There are many good police but by principle public prosecutors studied laws and work directly with them so they have better legal knowledge than the police, he said.
"The amendment is not based on good principles but rather a seizure of opportunity when the situation is not normal. But this is an important law for the country. We just can't let it go like this," Mr Kanit said.
Asked what people can do to change it back, Mr Kanit said since the NCPO was the sovereign power, its order was law and there was nothing anyone could do about it.
"The best we can hope for is to propose that the National Legislative Assembly amend it back," he said.
Lt Col Kamol Prachuabmoh, a former appointed senator and chairman of the Governing Officer Association of Thailand, submitted a letter to the NCPO on July 28 for the abrogation of the order.
He claimed it destroyed the balance of power principles of the country in criminal prosecution, according to an MCOT report.