The steel rockmesh installed on the cliffs south of the town following the 2016 earthquake - will be cleared of rock build-up.
Waka Kotahi journey manager Tresca Forrester says recent torrential rain has filled up some mesh fences with rock.
The half hour delays can be expected over the next two days on State Highway 1 between the Parititahi and Raramai tunnels, between 9am and 4.30pm.
