Three people have been arrested in a drugs bust involving million-dollar properties in Papakura and East Auckland.
Hundreds of cannabis plants were seized in the elaborate operation, with police saying they found an average of 60-80 plants at each of the six houses they searched on Thursday.
Five of the houses were rented and some were million-dollar plus properties.
"The houses have sustained some damage as a result of the activity taking place inside them," says Detective Senior Sergeant Kevin Tiernan, who is in charge of the investigation.
"Clearly the landlords for these properties have never done a house inspection in the time the property has been rented and they had no idea of the illegal use that was going on."
Snr Sgt Tiernan said if it can be proved that the landlords knew what was happening in the houses, police would look at taking proceeds of crime action against them and forfeiting the houses to the Crown.
More than 500 cannabis plants were seized on the day and have since been destroyed.
A man and woman, both aged 29, and a 42-year-old man have been charged with cultivating cannabis and were due before the Manukau District Court on Friday.