A driver is in hospital after his truck, which was carrying concrete slabs, rolled in Aongatete in Western Bay of Plenty Saturday morning.
Police said the driver climbed out of the truck and waited for emergency services after the crash just after 7am.
No other vehicles were involved.
One lane of State Highway 2, near the intersection with Thompsons Track, could be closed for several hours until a crane lifts the truck and trailer upright.
Motorists are advised to take alternative routes. Police are investigating the cause.