Last cannabis growing season Northland police destroyed 34,428 plants, made 47 arrests and recovered $33,000 of stolen property and vehicles.
Mr Pilmer said growers also opted to go indoors to have greater control over their crops.
However, sometimes it proved to be dangerous with people trying to bypass the legal power meters.
In Moerewa last week a fire was allegedly sparked by an indoor cannabis growing operation. Smoke was pouring from the upper floor of the two-storey home.
The blaze was quickly extinguished but the house was badly smoke damaged. No one was inside at the time, though people were in a sleepout on the same property.
A woman was charged and was scheduled to appear in the Kaikohe District Court.
Information can be left anonymously on a Crimestoppers tip-off line — 0800 555 111.