The drivers of two cars are to appear in the Levin District Court on Wednesday following a fatal crash in Foxton in February.
Two teenagers were killed when a car they were in lost control and rolled.
Police say speed was a factor, the car had seven passengers and neither of those killed were wearing a seatbelt.
The driver of one car, aged 19, faces two charges of manslaughter and four of dangerous driving causing injury.
The driver of a second car, aged 23, faces two charges of being party to manslaughter and four of being party to dangerous driving causing injury.
Police say the second car is linked to the crash.