A man has been charged with cultivating cannabis after police found more than 400 plants in three shipping containers in Whangarei - two of them buried.
Detective Sergeant Mike Blowers, head of the Organised Crime Unit, said the discovery would cause a serious dent in the local drug supply because the plants had the potential to produce hundreds of kilograms of cannabis.
The plants had a market value of about $1000 each and the find was a result of an anonymous call to the Crimestoppers phone line.
"It's definitely going to cause a serious dent, and will have a reasonably big impact on the local supply because there's quite a lot of plants here that'll be going out of circulation."
Usually police raids find between 20 and 50 plants and Mr Blowers said it was unusual to discover cultivation on such a large scale.
Most of the plants were in two shipping containers, about eight metres long, buried underneath a polythene house at a Whareora address.
A third shipping container was found above ground near the boundary fence. It contained more than 100 plants at various stages of growth and materials used for cultivating cannabis.
The search last Thursday uncovered 370 mature plants, 70 seedlings and clones.
"Clearly, these people would have put a lot of work into this one," Mr Blowers said.
A 45-year-old man has been charged with cultivating cannabis.
Mr Blowers said police also discovered four unsecured firearms and some ammunition in a separate search at the man's residence in Whangarei.
The find came a day after the seizure of several kilograms of cannabis in raids on tinnie houses in Auckland's eastern suburbs, which resulted in the arrest of five men and two women.
Several kilograms of the class C drug and several thousand dollars in cash were seized after search warrants were executed at three houses in Panmure, two in Pt England and another on a car.
The Auckland operation, codenamed Crest, was conducted by the Mt Wellington police tactical crime unit working with Housing New Zealand investigators.