Project introduction

The Southern Corridor Improvements project covers the stretch of Southern Motorway (SH1) from the SH20/SH1 connection at Manukau down to Papakura in the south. The Project includes additional lanes in both directions, upgraded Takanini Interchange and a 4.5km shared use pedestrian / cycle path.

  • Estimated project cost

    $356 million
  • Project type

    Infrastructure upgrade
  • Project status



The purpose of the project is to address existing bottlenecks at several locations along the Southern Motorway to provide a more reliable trip for all road users. There are also known safety risks at the Takanini Interchange, particularly at the northbound merge onto the motorway, which will be addressed as part of the Project.

Rapid population growth is expected in this area over the next 30 years. We need to meet the immediate needs of the city's growth as well as future proofing for the longer-term.



  • Improved journey reliability on the Southern Motorway (SH1).

  • More lanes to improve traffic flow.

  • Upgraded Takanini Interchange to improve safety and traffic flow.

  • Improved connections between the local roads and state highway network to ease congestion.

  • Improved walking and cycling facilities to connect communities.

  • Improved safety barriers and lighting.

  • New or improved noise walls, urban design and landscaping.

  • Improved stormwater treatment.

Latest progress

The Southern Corridor Improvements project was extremely complex with work taking place within a highly constrained and narrow motorway and urban arterial corridor, resulting in a staged construction approach to ensure the motorway and Great South Road continued to operate during the work.

All additional motorway lanes being delivered as part of the project were opened by December 2019. Final resurfacing and line marking of all motorway lanes between Takanini and Papakura interchanges was completed in September 2020.

Works on Great South Road and the motorway ramps at Takanini interchange were completed in early 2021.

The Southern Path, a 4.5km pedestrian and cycleway alongside the motorway, was opened in May 2021.

Project features

The Southern Corridor Improvements project included the following key features:

  • Southbound widening on the Southern Motorway to:
    • four lanes between the SH1/SH20 connection and Hill Road (previously three lanes).
    • three lanes between Hill Road and Papakura (previously two lanes).
  • Northbound widening on the Southern Motorway to:
    • three lanes from Papakura to Takanini (previously two lanes).
  • Upgrading the Takanini Interchange to provide new ramps and improved safety.
  • Walking and cycling improvements including a shared use path alongside the motorway from Takanini to Papakura.
  • Upgraded LED lighting and new median and shoulder barriers to improve safety.

Walking and cycling

A range of walking and cycling improvements formed part of the Southern Corridor Improvements project. These included:

  • Enhanced pedestrian and cyclist facilities through Takanini Interchange in the form of shared-use paths along both sides of Great South Road.
  • The Southern Path - a new 4.5km off-road pedestrian and cycleway along the corridor between Great South Road at Takanini interchange and Hingaia Road at Papakura Interchange. The path includes local connections at Brylee Drive, Conifer Grove reserve, and through esplanade reserves at Gardone Terrace, Pescara Point and Rushgreen Avenue.
  • The “Te Mara o Hine” pedestrian overbridge crossing the motorway on the south side of Pahurehure Inlet, then connecting into the Southern Path below.

Waka Kotahi NZ Transport Agency has developed a map showing how the Southern Path connects into the local walking and cycling network.

You can view the new Southern Path map below.

View larger image [PDF, 290 KB]

Project background

The Southern Motorway (SH1) is an essential part of Auckland’s transport network and is the primary route between Auckland, Hamilton and Tauranga. In 2013, the Government announced an accelerated programme for investment in key projects, including the Southern Corridor. The accelerated projects will help ensure that these routes, which provide the backbone to national economic growth and productivity, provide better links and improved journeys.

  • About the Southern Corridor

    The Southern Corridor is the stretch of Southern Motorway between the SH20/SH1 connection at the northern end and Papakura to the south.

    The Southern Corridor is a key strategic route from the north, connecting Auckland to Hamilton, Tauranga and the rest of New Zealand.

    Improvements to SH16 and SH20, with the completion of the Waterview Connection project in 2017 and the entire Western Ring Route in 2021, will increase the amount of traffic reaching SH1 heading southbound, in particular during peak times.

    Recent growth predictions forecast that Auckland’s population will grow by another one million residents over the next three decades. This includes an additional 160,000 people, equivalent to a city the size of Hamilton, located in the southern area alone.

    Our focus is on meeting the immediate demands of the city’s growth, whilst future-proofing for the long-term picture for Auckland to make the most of new infrastructure such as the completed Western Ring Route, City Rail Link, AMETI, additional Waitemata Harbour Crossing and the Puhoi to Wellsford motorway extension.

    The Transport Agency’s aim is to deliver an integrated and reliable journey to customers – whether travelling by car, truck, bike or public transport.

  • The problem

    Motorists experience frequent bottlenecks at several locations along the Southern Motorway, in particular between the SH20/SH1 connection and Papakura, including the Takanini Interchange, creating significant delays and eroding journey reliability. This is caused by an imbalance in the number of lanes heading both northbound and southbound with the fluctuation from three to two lanes.

    Additionally, growth in South Auckland is increasing the amount of congestion on the local road network at Great South Road with frequent delays for motorists and buses. This is also having an effect on traffic entering and exiting the motorway at the Takanini Interchange. There are also known safety risks at the Takanini Interchange, particularly with the northbound merge onto the motorway.

    A lack of walking and cycling facilities along the southern corridor means fewer trips are made by foot or bike, leading to increased car use for short distance trips.