Arthur's Pass will remain closed today with those wanting to head to the West Coast needing to add another hour-and-a-half to their journey.
State Highway 73 was expected to reopen at the weekend.
However, a Christchurch Transport Operations Centre spokesperson says heavy rain and bad weather has meant the slip site on State Highway 73 between Jacksons and Arthur's Pass is saturated, making it difficult for contractors to clear.
The slip – caused by last week's bad weather - is bigger than the original estimate of 20,000 cubic metres. It is between 40,000 to 50,000 cubic metres.
Contractors yesterday were working to clear an estimated 9000 cubic metres.
Weather depending, the road could re-open tomorrow. It will be down to a single lane at the slip site opening to traffic for ten minutes on the hour, every hour between 8am – 7am.
The road has been closed since Wednesday night with the main access to the West Coast currently through the Lewis Pass.