The Ombudsman is demanding the Public Health Ministry justify its regulation that classifies people in possession of five methamphetamine pills or 10mg of crystal meth or less as mere drug users, as opposed to dealers, within 30 days.
The Office of the Ombudsman is looking to cancel the ministry regulation.
Pol Lt Col Keirov Krittateeranon, secretary-general of the Office of the Ombudsman, on Saturday said the office is keen to know how the regulation will curb "social disobedience" as claimed.
The information will be used by the Ombudsman in its decision.
The order came after Pol Maj Gen Vichai Sangprapai, former deputy commander of the Metropolitan Police Bureau, submitted a petition to the Office of the Ombudsman on Friday regarding the regulation.
Pol Maj Gen Vichai said that the regulation violates Thailand's constitution and might do more harm than good.
He said it could pave the way for addicts to turn to dealing and lead to more social harm, such as crime and disorder.
Moreover, the regulation could lead to an increase in bribery cases involving corrupt police who would intentionally overlook the amount of drugs people possessed in exchange for money, he said.
Dealers would then be categorised as users who need rehabilitation instead of being sent to jail, he added.
He said the regulation may not even help with drug suppression. It also does not reduce the number of prisoners as allowing drug users to go free can lead to an increased crime rate, he said.
He said anti-drug regulations should be more effective, noting that meth pills cause hallucinations and aggression no matter many a person consumes.
On average, each police station in the country handles five cases of violence related to meth on a daily bases, he said.
"If people are treated as patients, why does violence continue?" he said.
The government has no data on whether those who undergo rehabilitation go back to using drugs again, he said.
"[The health ministry] regulation is dangerous and I will fight it with all my might," he noted.
Pol Lt Col Keirov said Pol Maj Gen Vichai's petition seeks the cancellation of the regulation, which can be done if the Ombudsman agrees that the regulation opposes the constitution or other laws.
If so, the matter will be forwarded to the Administrative Court for a decision, he said.
He said the Office of the Ombudsman would send a letter to the Ministry of Public Health explaining the matter within 30 days.