The first arrests were made when the armed offenders squad searched a Mongrel Mob property in Middleton Rd on Friday night after a series of fires in Dunedin earlier in the day, Detective Sergeant John Hedges said.
One of the fires burned out the lounge of a Fingall St property associated with the Black Power gang.
Several Molotov cocktails were thrown at other houses with gang connections the same night.
Two men later arrested at a gang house faced drugs charges, Det Sgt Hedges said.
Yesterday, armed police seized two loaded sawn-off shotguns, a stolen Subaru and large quantities of cannabis when they searched Black Power houses at Henley and Canongate.
The searches related to the drive-by shooting at a South Dunedin house on Waitangi Day.
Det Sgt Hedges said police were disappointed the shotguns were loaded when found.
Two men were arrested on drugs charges and given police bail.
Those already charged are due to appear in the Dunedin District Court on Friday.
