State Highway 6 on the West Coast is expected to remain closed until at least mid-day tomorrow after a large piece of the cliff wall fell on the road.
The boulder is blocking the road near Barrytown in the Grey District - the main road between Punakaiki to Greymouth.
Police said the rock will likely keep the road closed until mid-day, but Waka Kotahi said the road was now closed for the weekend and the next update will be on Monday afternoon.
Police are advising motorists to use an alternative route.
