The parcels were seized at the Therd Thai post office in Mae Fa Luang district on Monday after the parcels failed to clear customs check and were returned to the sender.
The name on sending address was Alu Futua, a resident of Tambon Mae Salong in Mae Fa Luang. After he failed to turn up to retrieve the parcels, police checked the contents and found 30 bags of heroin hidden among bags of cooking ingredients.