State Highway 1 is partially closed near Levin after a crash involving a truck and trailer this morning.
Rail services have also been suspended as the truck was left precariously near the tracks.
Police and fire crews were called to the scene at the Manakau overbridge near Levin just before 8am.
/arc-anglerfish-syd-prod-nzme.s3.amazonaws.com/public/4G7IFJ3UOVBWVLSCWWJUT64LDE.png 320w,//www.nzherald.co.nz/resizer/nTFaOMY8kU4cs8TQMc8ghVhpXqw=/375x208/smart/filters:quality(70)/arc-anglerfish-syd-prod-nzme.s3.amazonaws.com/public/4G7IFJ3UOVBWVLSCWWJUT64LDE.png 375w,//www.nzherald.co.nz/resizer/SwdzIYJGesAJ3m-y8NS0bspQij8=/660x367/smart/filters:quality(70)/arc-anglerfish-syd-prod-nzme.s3.amazonaws.com/public/4G7IFJ3UOVBWVLSCWWJUT64LDE.png 660w,//www.nzherald.co.nz/resizer/PzpnROKMXdYrHuSWZQuZke0Z04M=/810x450/smart/filters:quality(70)/arc-anglerfish-syd-prod-nzme.s3.amazonaws.com/public/4G7IFJ3UOVBWVLSCWWJUT64LDE.png 810w,//www.nzherald.co.nz/resizer/j_haMVVeF2MCpVGaEVJ06OxAE2g=/970x539/smart/filters:quality(70)/arc-anglerfish-syd-prod-nzme.s3.amazonaws.com/public/4G7IFJ3UOVBWVLSCWWJUT64LDE.png 970w,//www.nzherald.co.nz/resizer/hsH8DmnWIe1enpiPk0E_9B94yWM=/1440x800/smart/filters:quality(70)/arc-anglerfish-syd-prod-nzme.s3.amazonaws.com/public/4G7IFJ3UOVBWVLSCWWJUT64LDE.png 1440w)
/arc-anglerfish-syd-prod-nzme.s3.amazonaws.com/public/4G7IFJ3UOVBWVLSCWWJUT64LDE.png 320w,//www.nzherald.co.nz/resizer/nTFaOMY8kU4cs8TQMc8ghVhpXqw=/375x208/smart/filters:quality(70)/arc-anglerfish-syd-prod-nzme.s3.amazonaws.com/public/4G7IFJ3UOVBWVLSCWWJUT64LDE.png 375w,//www.nzherald.co.nz/resizer/vBC5Oh68VYS_rF_HrSMMavGGuTA=/620x344/smart/filters:quality(70)/arc-anglerfish-syd-prod-nzme.s3.amazonaws.com/public/4G7IFJ3UOVBWVLSCWWJUT64LDE.png 620w)
Senior Sergeant Sarn Paroli said the southbound truck and the northbound car had collided head-on on the south side of the rail bridge.
"The driver of the car, a man in his thirties, was airlifted to Palmerston North Hospital with serious injuries."
Paroli said the truck driver was uninjured by shaken.
A heavy tow truck was required to clear the truck from the road.
Pavoli warned the scene would not be cleared for a few hours and motorists should avoid the area, if possible.
"The priority is opening up the road," he said. "But doing that depends on whether we can safely retrieve the truck and trailer."
One lane was opened just after 10am.
KiwiRail inspector Eddie Dargaville said the track would also be closed until further notice.
A resident, who lives near the accident scene and declined to be named, said the site was notorious for accidents.
"In the 50 years I've lived here, I would have seen hundreds of accidents," she said.
The woman said the speed limit should be lowered on the stretch of road between the rail overbridge and the Waikawa Stream bridge.
Further up the country, a crash was causing traffic headaches for motorists on the Northern Motorway.
The collision was blocking the right-hand lane of the Onewa on-ramp.