Contractors have mounted a huge operation to clear a 20,000 cubic-metre slip blocking State Highway 73 between Christchurch and the West Coast.
A New Zealand Transport Agency spokesperson said 16 trucks, five excavators, four dump trucks, a large bulldozer and three wheel-loaders were involved in the project.
While it and other slips isolated Arthur's Pass, the way through from Christchurch was cleared yesterday.
The agency was worried more heavy rain scheduled for today and Sunday could make the work harder, the spokesperson said.
Drivers wanting to reach the West Coast from Canterbury would have to use State Highway 7 through Lewis Pass, adding 1.5 hours to the journey.