Police say a sizeable dent has been made in an underground cannabis market in the north Waikato

A black rubbish bag filled with cannabis was seized from a 16-year-old after a car was spotted driving dangerously around the town of Tuakau - trying to evade police.

An Eagle helicopter was deployed, before the vehicle was eventually pulled over and the teenager taken into custody.

Senior Sergeant Anton Maisey says offenders are making huge profits from the illegal drug trade, and any catch on this scale should send a warning to people buying or selling, that they will be held to account.