- State Highway 73 between Arthur's Pass village and Otira will remain closed until at least midday on Saturday after heavy rain triggered more rockfall.
- The highway will be reassessed on Saturday to determine if it can be reopened.
- The Lewis Pass is an alternative route between Christchurch and the West Coast, adding about an hour to the trip.
- More heavy rain is forecast through to next Tuesday which may mean further closures on the highway.
A key route between the West Coast and Canterbury will remain closed until at least Saturday midday due to rockfall.
State Highway 73 was closed early on Friday morning when heavy rain brought down more rocks and debris onto the road at the western side of the Rock Shelter, near the Otira Viaduct.
NZ Transport Agency West Coast maintenance contract manager Moira Whinham said the rockfall started on Tuesday and prompted a short closure, but it restarted on Friday due to heavy rain.
"Our first concern is the safety of our teams and road users and until conditions stabilise enough to allow safe access to clear the area the road will remain closed," she said.
"The conditions will be reassessed on Saturday to determine whether it will be safe to open during daylight hours going forward."
The next update was expected at midday on Saturday.
There was an alternative route between Christchurch and the West Coast via the Lewis Pass, which added about an hour to a trip.
Motorists were warned there might be ongoing periods of closures on State Highway 73, as more heavy rain was forecast to hit the West Coast and Main Divide through to Tuesday next week.