Bad weather and the risk of rockfalls has forced the closure of State Highway 1 south of Kaikoura.
The road, which was badly damaged in November's magnitude 7.8 earthquake, has been closed between Peketa and Goose Bay.
It was expected to be closed until tomorrow.
Motorists travelling to Kaikoura in the meantime have been advised to use Inland Route 70 between Culverden and Kaikoura.
The closure comes during the busy summer tourism season as the region works to rebuild after the quakes.
It was only yesterday, seven weeks after the big quake hit, that Whale Watch Kaikoura was finally able to send out a tour boat.
The business is Kaikoura's largest tourism operator, and marketing manager Lisa Bond said everyone understood how "momentous" the occasion was.
Meanwhile, traffic remains limited to one lane at the scene of a crash on State Highway 6 between Lumsden and Dipton while palm kernel is removed from the road.
A trailer containing the product overturned about 11.15am, spilling its contents, while being towed by a truck.
Police said the driver was not hurt in the incident, which happened near the intersection with Caroline Valley Rd.
Road users were advised to expect delays.
- additional reporting Otago Daily Times