Two people have been taken via helicopter to different hospitals after rolling their car near Waiouru early on Thursday.
Emergency services responded to the incident on SH49 just outside Waiouru at 1.40am.
The three people involved were out of the vehicle on arrival.
A St John spokeswoman said two ambulances and two helicopters were sent to the scene.
One person was flown to Palmerston North Hospital in a serious condition, and another person in serious condition was flown to Hawke's Bay Hospital.