State Highway 6 has been re-opened to a single lane on Thursday following work to clear a large slip.
Rocks up to 10 metres wide came down about 11pm on Wednesday, blocking the road from Makarora to Hawea in the Queenstown-Lakes District.
The open lane is being controlled with temporary traffic signals.
Further work will be done with the aim of having both lanes operating by the middle of next week.
Contractors and geotechnical engineers are on site to stabilise the 50-metre-high dropout, as rocks continue to fall.