One person died in a road accident at Pongaroa, near Dannevirke.
The crash occurred on Route 52, shortly after midnight.
The Palmerston North Rescue Helicopter was sent there and its crew had to use night vision goggles.
They couldn't land at the accident site because of poor weather so had to land at the township.
One person died at the scene.
Another person with life-threatening injuries had to be stabilised before being transferred by ambulance to the helicopter and airlifted to Palmerston North Hospital.
A third person has minor injuries.