A man has been arrested in relation to supplying synthetic drugs at a Manakau address, in Horowhen.
During the search a pump action shotgun and 56 rounds of ammunition were located, as well as nearly four kilograms of material used in the manufacture of synthetic drugs.
"This is a significant quantity and once manufactured these materials would have an estimated street value of $100,000," says detective Sergeant Karen Heald.
The 26-year-old has been charged with supplying a psychoactive substance and bailed to appear in the Levin District Court on Thursday, November 16.
"Synthetic drugs cause significant harm to the community and can be fatal to users.
"Police are committed to holding those responsible for manufacturing and dealing these dangerous substances to account.
"We encourage anyone with information in relation to its manufacture and supply to contact police"