Two men are in custody and a woman is on bail on drugs charges after the police searched properties in Marlborough.
A Tasman Police Districts spokesperson said the arrests were made after they recovered methamphetamine, cannabis, 24 firearms and a large amount of stolen property, dating back two years.
The men, both aged 35, were to appear in the Marlborough District Court on 7 March, and the 25-year-old woman was expected to appear a week later.
Meanwhile, the police said more than 120 cannabis plants and 2kg of dried cannabis had been found at properties in Westport/Buller, after an operation targeting drug offending.
Two people have been charged with drug-related offences, and officers were searching for a third.