The driver of a crashed truck managed to walk away after it ended upside down in a fast flowing river.
The vehicle carrying a load of potato chips crashed off State Highway 1, just north of Mangaweka, and into the Rangitikei river at about 5am, landing on its roof in the water.
Other truckers on the road stopped to help, climbing down the bank, breaking a window in the cab and hauling the driver out.
Police said the driver - who is aged in his fifties - was able to walk to a waiting ambulance, before being transferred to the Palmerston North-based rescue helicopter.
He was now under observation in Palmerston North hospital, in a serious but stable condition.
The three lanes in the area have now been reduced to two lanes and police are asking motorists to take care in the area.