Multiple people have been arrested and cash, guns and drugs seized in a police operation targeting gangs in Hawke's Bay and Tairāwhiti.

Operation Bloodhound targeted Black Power and Mongrel Mob members and associates.

More than 30 people associated with gangs are facing charges and more than 30 firearms have been seized in the operation since March 21.

Approximately $100,000 in cash was found by police at a Napier gang headquarters on Wednesday.

A Hawke's Bay man was believed to be making firearms and other weapons.

In a search at the man's rural property, homemade pistols, improvised explosive devices (IEDs) and other gun parts and ammunition was found by police. Cannabis plants and drug utensils were also found.

Meanwhile, police say: "In one traffic stop, police located approximately $14,000 cash in the vehicle, as well a number of weapons and drug utensils. An investigation into this matter is ongoing and several charges are likely"

Detective Inspector de Lange says: “Eastern District Police have absolutely no tolerance for offending by gang members and associates in our communities".