The controversial advice is contained in a draft circular issued for consultation by the Northern Ireland Department of Education.
It says experimentation with drugs often starts at 14, but that 6 per cent of Northern Ireland 11-year-olds claim to have been offered drugs.
The draft circular says that pupils suspected of possessing drugs should be detained under supervision while the police are called in to deal with the situation. Intimate physical searches should never be made by a member of staff, it adds.
The National Association of SchoolmastersUnion of Women Teachers said it was "wholly unreasonable" to ask teachers to take these actions. "The attendant risks which teachers face in following this advice do not appear to have been a consideration," said Tom McKee, the association's Northern Ireland officer.