The Transport Agency has begun working around the clock to clear the massive slip in the Manawatu Gorge.
The section of State Highway 3 has been closed since August, when the first of several slips brought down more than 300,000 cubic metres of hillside.
Heavy machinery has in recent months carved out terraces, in a process known as benching, which has made it safer to clear the lower part of the slip.
The Transport Agency says about 230,000 cubic metres of material has been removed and about 85,000 cubic metres remains.
Spokesperson David McGonigal says they have begun working through the night and the site should be cleared within three to six weeks.
Some bridges will need to be repaired, but the agency is still on track for a mid-year re-opening of the gorge.
It says it will look at using temporary bridges if that is what's required.