The work includes widening State Highway 1 (though not extending or putting in new passing lanes); removing tight corners and installing a median wire rope barrier to separate north and south-bound traffic.
It will also provide a place for people to stop and admire the tremendous views from atop the hill, with a new look-out over Bream Bay, Hen and Chicken Islands and the Waipu Plains being constructed.
Agency highway manager Brett Gliddon said the project was a large-scale one and there would be some disruption for drivers as some of the passing lanes would be shortened or closed, and people would need to drive with care and to be patient.
Contractors will work between 7am and 7pm. The work will be done in stages and no night work is planned.