Significant changes to the road layout on State Highway 2/Maunganui Rd, near the Bayfair roundabout, are scheduled to take place this week.
The work is part of the Bay Link project.
A Waki Kotahi NZTA statement said, with work on the five ground improvement sites nearly complete, the focus for the northern end of the project is construction of the underpass and Bayfair flyover.
The next phase involves constructing a temporary road in the middle of the current work zone north of the Bayfair roundabout.
Traffic will be moved across to the centre of SH2/Maunganui Rd to allow space for the new cyclist and pedestrian underpass to be constructed either side.