Thousands in cash and a kilo of meth have been seized, and four people have been arrested in Whanganui as part of Operation Arch.
Police said it was targeting the distribution of illegal drugs in Central District.
The Whanganui Organised Crime Unit (OCU) confiscated about $70,000 in cash, as well as 1 kg of methamphetamine and other controlled substances during an operation conducted late last week.
Three men, aged 46, 47, and 53, and a 31-year-old woman were arrested, facing charges of possessing methamphetamine or GBL for supply and unlawful possession of a firearm.
They appeared in Levin and Whanganui Courts on 23 and 24 November and are remanded in custody.
Two of the men, apprehended in Levin, were found in possession of a substantial quantity of drugs and cash. The third man was arrested at a Waverly residence by the Armed Offenders' Squad (AOS).
Further search warrants targeting assets were executed in Whanganui, resulting in the arrest of the woman.
Acting detective Senior Sergeant Carey Priest said the operation was a joint effort from a number of different teams.
"The proactive and can-do stance of the investigation team has bought together our resources effectively to remove a significant quantity of harmful drugs from our community and to hold those responsible for their distribution to account."
Anyone with information on illegal drugs in communities is asked to contact police.