Thailand is trying crack down on drugs

Parental consent for the tests will be sought, and officials say those found to have used drugs will be treated, and their records kept confidential.

"Schools should not solve the problem by expelling students who are found to be addicted to drugs," Mr Purachai told national television. "They should help them in rehabilitation."

Rasamee Witawaid, Deputy Secretary General of the Thai Narcotics Control Board told BBC's East Asia Today programme: "We want to help them, rehabilitate them in the school, in the family. That's the point. It's not to blame them."

Young drug users

The trafficking and consumption of methamphetamine is a major social problem in Thailand.

In November, a health ministry survey found that 2.65 million Thais, or 4.3% of the population, were addicted to drugs. Of those people, 91% were hooked on methamphetamine, which is mostly smuggled in from neighbouring Burma.

The authorities are also concerned about ya baa, or mad medicine, which is becoming increasingly popular among young people. The average age of first-time users is 13, the authorities say.

The drug has been found everywhere from primary schools to nightclubs. According to the United Nations, 800 million tablets were trafficked in Thailand in 2000, enough for 12 per person.

In October Mr Purachai won widespread public support for a social order campaign forcing nightclubs to close early in an attempt to curb drug abuse and underage drinking among Thai youth.