Helicopters have been dropping water on the hillside along the Manawatu Gorge Road to try to clear a massive landslide which is blocking the highway.
The section of State Highway 3 has been closed since Thursday night after about 1000 cubic metres of soil and debris came down onto the road, about 2km from the Ashhurst end of the gorge.
The Transport Agency said on Saturday the helicopters are attempting to wash loose debris down from the hillside so contractors can clear it with diggers over the next week.
Regional state highways manager David McGonigal said the road was unlikely to reopen until Friday at the earliest.
Drivers are able to use the Pahiatua Track and Saddle Road as alternatives.