"Villagers have frequently complained of suspicious gatherings in temples and most of them are drug users or people involved with drugs," said a local government official who did not want to be named.
Those who undergo rehabilitation and stop using drugs will be allowed to re-enter the monkhood, he added.
Thailand's Buddhist clergy has been hit by a series of scandals, with local media reporting cases of drug-taking, drinking, gambling and visiting prostitutes.
Recent footage of three monks flying in a private jet with sunglasses and a Louis Vuitton luxury bag sparked a furore in the Buddhist-dominated country.
One of the trio, Luang Pu Nen Kham, is also being investigated on suspicion of an array of offences including sex with a minor, tax evasion, drug possession and money laundering, according to the Justice Ministry's Department of Special Investigation.
He is now overseas although his exact whereabouts are unclear. Buddhist authorities said they would ask the Thai foreign ministry to revoke his passport.