Asian crime syndicates are using foreign pupils in some of Auckland's best high schools to receive illegal shipments of the drugs used to produce methamphetamine.
Police believe the Asian pupils - known as "catchers" - are receiving dozens of parcels containing pseudoephedrine-based ContacNT cold tablets a month.
Pseudoephedrine is the base ingredient in methamphetamine, the drug group that includes P.
Police say about 30 packages containing ContacNT - often buried among chocolate and noodles - were intercepted by Customs last month.
Detective Senior Sergeant Chris Cahill of the Auckland Metro drug squad said "at least that many, maybe more", could be coming into the country every month.
Pupils at high schools all over Auckland have been recruited.
Their schools include Auckland Grammar, Takapuna Grammar, Mt Roskill Grammar and Avondale College.
Ten pupils have been arrested in the past three months and are before the courts, and well over 100 have been caught receiving the drug shipments in the past five years.
The parcels are sent to New Zealand by Asian-organised crime syndicates and contain up to 2kg of ContacNT, enough to make hundreds of thousands of dollars worth of methamphetamine.
Catchers are believed to receive up to $1000 for every parcel they receive.
"A kilogram sells for about $6000 and has the potential to make about $240,000 worth of methamphetamine," Mr Cahill said.
Customs investigations manager Mark Day said pupils and young people were being "used and victimised" as catchers.
He said officers found pseudoephedrine most weeks - often several times a week - mainly in mail coming from China.
ContacNT is legal in China, but is a Class C drug in New Zealand and importing it carries a maximum penalty of eight years in prison.
