A 17-year-old man's been charged over a fatal crash in Pahiatua.

Cheyenne Ihaka, 16, died in the two car head-on crash on State Highway 2 in July and a woman in another vehicle was seriously injured.

A preliminary investigation suggested the dead boy was the driver and the 17 year old was the passenger.

Detective Senior Sergeant Craig Sheridan says after significant inquiries and witness interviews, they've established Cheyenne wasn't the driver - and the 17-year-old staged the situation.

He's now been charged with attempting to pervert the course of justice, careless driving causing death and careless driving causing injury.