The raids, which took place in Mairehau, were part of a large-scale probe in the city.
At least five properties were searched and police uncovered several big cannabis operations, a large amount of cash and unspecified items.
A police spokeswoman said three people have been arrested, including a man in his 40s and a man in his 50s, who are due to appear in court on October 20.
Another person has been ordered to appear in court.
The spokeswoman said the overall investigation is ongoing.
Neighbours of a raided Mairehau house revealed they had no idea a cannabis growing operation was next to them.
A neighbour said he noticed multiple police vehicles on his street about 8am, which he said was "unusual" for the area.
He had no idea what was going on until the police started pulling out of the house what looked like cannabis growing equipment, including air vents and a large number of fertiliser containers.
