Children younger than five have been caught up in a major police investigation into the methamphetamine trade in Gisborne and Rotorua.
Forty-one people collectively face 245 charges including importing a class-A drug, conspiring to sell, and selling and possession of methamphetamine.
Property worth $3.8 million has also been seized, along with bank accounts and vehicles, after 37 properties in Gisborne and Rotorua were searched.
Detective Sergeant Kevin Ford said the number of children found around drug use was worrying.
There are 10 houses that were particular worrying where children were exposed to drug use and criminal activity. These families have been referred to social services, he said.
Police said 700 grams of methamphetamine had been imported and was destined for the Gisborne and East Coast market.
The operation culminated last week after an eight-month investigation but police have only just released details.
Four Singaporean nationals were among those charged.
Those arrested included patched Black Power and Mongrel Mob members and several others with strong family ties to the gangs.
The arrested people have been appearing in courts in Auckland and Gisborne over the past nine days.
Families of the children involved have been referred to Child, Youth and Family.