Assets worth $1.6 million have been seized in more than a dozen raids on the Mongrel Mob and its associates in Hawke's Bay.
Six people have been arrested following the execution of 14 search warrants across the region on Tuesday morning.
Assets seized include four houses, vehicles and motorbikes, as well as approximately $110,000 cash.
1.5 kilograms of cannabis and seven firearms were also found.
Five men and one woman have been arrested and charged with numerous offences, including possession of firearms, possession of cannabis for supply and participation in an organised criminal group.
Police said further arrests and charges are likely.
Detective Inspector Mike Foster said the search warrants were the result of 12 months of an ongoing operation by the Hawke's Bay Organised Crime Unit into the sale of illegal drugs throughout the region.
"Organised crime is all about money," he said. "Attacking the profits of organised criminal groups is a key part of our strategy to deter and disrupt their operations, and combat the illegal activities they're involved in."
Tuesday's operation was an extension to a previous operation in May, which saw 16 people arrested and approximately $1,000,000 in assets restrained.
Police said information regarding organised crime and gang-related offending from the community is invaluable in helping police.
Information can be provided to Police via 105 (phone or online reporting), or anonymously via Crimestoppers on 0800 555 111.