Police believe a Manawatu Prison inmate allegedly selling and supplying methamphetamine had community help.
Six people linked to the findings appeared in Palmerston North District Court on Wednesday on drug supply and firearm charges.
Police said their search revealed the prisoner used community contacts to distribute the drug.
"Methamphetamine is a harmful drug that is damaging our communities," said Senior Sergeant Simon Harrison.
"Our actions today show that when it comes to investigating the selling of this drug, nowhere and no one is off limits to the police."