Police have arrested four people and seized more than 4000 cannabis plants in Northland during a search warrant.
In a release today, police said 20 staff were involved in the drug bust, which took place on Oturei Settlement Road near Aratapu last Thursday.
Officers found five glass houses filled with cannabis plants, with one of the glass houses being more than 60 metres wide.
Four people were found on the property - men between the ages of 20 and 45 - and all were arrested and charged with cultivating cannabis.
They are due to appear at Whangārei District Court next week, and police say they may add further charges.
Police also warned that the operation which led to the bust is ongoing, and further seizures are possible.
Detective senior sergeant Geoff McCarthy said the operation was sophisticated and well established, with some plants up to 2.5 metres tall.
"This is one of the most significant cannabis seizures police have made in the Northland District for a number of years," Mr McCarthy said.