The Maungatapu underpass will open to traffic on Friday, the New Zealand Transport Agency has announced.
Construction on the $45 million project started in September 2015.
A temporary 50km/h speed limit will apply to the 120m long underpass, which connects
Welcome Bay and Turret roads underneath State Highway 29A and the Maungatapu roundabout.
New traffic lights will be operating at the Welcome Bay Road and Welcome Bay Link Road intersection.
A temporary stop sign will be installed at Hairini Street. Drivers will be encouraged to use the access from the Maungatapu roundabout.