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.
A third person had moderate injuries and was not taken to hospital.
Fire and Emergency New Zealand assisted at the scene by making a safe landing pad for the helicopter, and helping with traffic management and scene protection.
At around 8.40am on Thursday, emergency services were called to another single vehicle accident on Halcombe Rd, north of Feilding.
The car hit a power pole just south of Mt Taylor Drive. The power pole came down across the road and traffic had to be diverted.
Power was lost to 1326 customers due to the crash after bringing down powerlines. Power was restored to the customers just after 12.30pm.