The Manawatu Gorge will be closed for two days next week so that engineers can realign the road.
The route was shut for nine months after 370,000 cubic metres of debris fell on the road in August.
It partially reopened last month.
The Transport Agency is closing the gorge again for two days to allow it to move the road closer to the hillside.
Palmerston North state highways manager David McGonigal says the road is being moved closer to the hillside.
This will reduce the effects of erosion below the road and give drivers a greater sense of security.
The road will be closed from 8am on Monday - 6pm on Tuesday.
