State Highway 49 near Rangataua Road, just out of Ohakune, is currently blocked.
Emergency services were notified that a truck carrying dairy products rolled around 1.50pm, says a police spokesperson.
"The driver is not seriously injured but the road may be blocked for some time.
"A crane is on its way to move the truck, cleaners are on their way and diversions are being put in place.
"Motorists are thanked in advance for their patience."