State Highway 36 between Tauranga and Rotorua will remain closed for the next two weeks at least.
The Transport Agency expects draft reports in a few days on the cause of a major rock fall on 6 August which crushed a moving car in the Mangorewa Gorge.
The agency says investigations into the rock fall in the gorge are continuing. Contractors are working to secure the area, as well as replace existing bridges and shore-up retaining walls.
The target date for reopening the highway is Monday 14 September, pending the completion of safety works.
However, motorists then face another four weeks of single lane traffic through the construction site near Kaharoa.