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Project introduction

The Maungatapu underpass is a two lane link underneath the Maungatapu roundabout, improving the traffic flow around the Maungatapu and Hairini roundabouts. It connects Welcome Bay Road to the Turret Road causeway and a new bridge constructed over the Kaitemako Stream.

  • Estimated project cost

    $45 million
  • Project type

    Road improvements
  • Project status



The project aimed to ensure travel times and safety levels are improved as the volume of traffic increases in line with the predicted growth of the southern suburbs.




Benefits of the Maungatapu underpass:

  • Improves the safety and movement of local traffic on key urban roads, separating State Highway 29A from local traffic.
  • Provides a long-term benefit in solving congestion at the Hairini and Maungatapu roundabouts.
  • Safer for pedestrians and cyclists.


About the project

The four project phases include:

Stage 1 – Completed December 2008
Traffic signals added to the Maungatapu and Hairini roundabouts.

Stage 2 – Completed March 2011
Improvements to the Fraser Streer/15th Avenue intersection and pedestrian and cycling facilities.

Stage 3 – Investigation
Four-laning from the Cameron Road intersection to the Maungatapu and Hairini roundabouts, including a new duplicate bridge across the causeway.

The outcome of the investigation showed no work is required in the short to medium term within this corridor, although, a better understanding of the wider roading network is required to clarify the longer term needs, and ultimate form of this important transportation corridor.

Stage 4 – Maungatapu underpass design and construction
An underpass was identified as the best way to separate the local traffic from the traffic on SH29A. The two lane link underneath the Maungatapu roundabout will connect directly to Welcome Bay road and will improve traffic flow around the Maungatapu and Hairini roundabouts.

Features of the Maungatapu underpass include:

  • It will be constructed under SH29A, separating local and state highway traffic.
  • It will link Welcome Bay Road to the Hairini causeway directly.
  • A new bridge over Kaitemako Stream will be constructed.

Latest video update

Our partners on this project