After that, the crews will move to Waikoau Hill and aim to finish the work there by the end of June.
During the work, stop/stop traffic management will be in place, causing delays of 15 to 25 minutes before the lanes are reopened to traffic.
However, access will be maintained for emergency services, and they will be assisted through the work site.
The decision to carry out the rock scaling was made after a geotechnical assessment revealed the presence of more loose rock at both sites, which were previously scaled for rocks following Cyclone Gabrielle.
The NZTA/Waka Kotahi spokesman expressed gratitude to motorists for their support during this critical work.