An investigation by police that began in June with the interception by Customs of a drugs shipment has resulted in an arrest and the seizure of firearms and more than 10kg of synthetic cannabis.
Police's Operation Tiger culminated in raids on nine addresses in Auckland, Palmerston North and Christchurch on Thursday.
Ten kilograms of synthetic cannabis and four firearms were seized.
A 48-year-old man will be appearing in the Waitakere District Court on charges relating to possession of a firearm and ammunition as well as possession of a Class A drug.
Last week, 2kg of AMB-Fubinaca - the psychoactive substances used in the manufacture of synthetic cannabis - was seized during raids in Rodney, north of Auckland, while on Thursday another 1kg was taken off the street.
The 3kg of AMB-Fubinaca would be sufficient to manufacture 150kg of synthetic cannabis - worth a street value of $1.5 million.
The investigation began in June with the Customs seizure and this is just the tipping point, says Acting Detective Inspector Roger Small.
"We are confident that further arrests will come as we continue to investigate this serious issue," he said.
Customs Intelligence Manager Wei-Jiat Tan said interceptions at the border are a good indication of new and emerging drugs, and Customs
shares this with police to disrupt production and supply in the regions.
"Chemical properties of psychoactive drugs are ever-evolving and potentially lethal, especially if amateurs are producing them," he said.
"These drugs can be life threatening for users, who have no way of knowing what they're really taking."