A 400-metre slip continues to block the road to the West Coast glaciers.
The landslide came down between Whataroa and Harihari late Thursday night. Five people in two vehicles had to be rescued.
Transport Agency West Coast maintenance contract manager Moira Whinhan says the material sits about four to five metres above the road level.
"What's happened is a debris slide - it's come down with a lot of vegetation, and that's got mixed up in the gravel on the surface of the hill."
Ms Whinhan says there's no clear indication of what damage has been done at this stage.
"It's significant, it's major, it's a lot of work to get it reopened. There's excavators, loaders and trucks supporting that. There are probably 25 to 30 people working there."
An update will be made on Monday with information on the road re-opening - but limited traffic could be allowed through before then.
"We're hoping that we may have parts of it down to road level probably Sunday, but it's unclear at this stage. The material's quite difficult to work with because it's full of trees."
The slip has, for the first time in 20 years, caused the West Coast's biggest A&P show, set to be held in Whataroa, to be cancelled.
Westland Mayor Bruce Smith says there would already have been a big number of exhibitors and people in the area preparing.
"It's in the hand of the gods when it comes to how much rain we get. We had good, solid rain here that wasn't record-breaking by any stretch of the imagination, but it was a good shower."
Mr Smith says he can't remember a landslide as big as the one that's knocked out a key section of West Coast highway.
He thinks the road will be shot, but is sure the rebuild won't take long.