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.