SH20 Airport Route Changes


Significant changes to Auckland’s SH20 and the Walmsley Road on ramp at Mangere Bridge from Monday.

The additional third southbound lane under the Walmsley Road on ramp will be opened early on Monday morning for traffic heading to Auckland International Airport and to Manukau.

At the same time, safety improvements to the on ramp become operational and traffic using it will no longer be able to “weave” across the motorway to join SH20A for the airport.  They will be prevented from doing so by a 900 metre-long barrier between the on ramp and the motorway that will direct all on ramp traffic to Manukau and beyond.

The improvements mark the end of construction around the Manukau Harbour Crossing project involving Fletcher Building, Beca, Higgins and the NZTA.

NZTA’s Project Services Manager, Tom Newson, says the improvements around Walmsley Road will help provide safer and more reliable journey times for those heading to the airport and further south. The wider section of motorway will help ease congestion, particularly at peak times, and the on ramp barrier will improve safety and stop people from trying to cross high speed motorway lanes to go to the airport.

People who normally use Walmsley Road to access the airport will be directed on to local roads.

The on ramp and the southbound lanes of the Southwestern Motorway from Walmsley Road to Kirkbride Road (SH20A) and Massey Road (SH20) will be closed from 9pm this Sunday until 5am the next morning to allow contractors to complete the changes.  Airport traffic will be diverted from Walmsley Road to McKenzie and Kirkbride Roads.  Traffic for Manukau and further south will be diverted along Walmsley and Robertson Roads to Massey Road. The closure will be weather dependent.

All northbound lanes of the motorway are not affected and will remain open.

Contractors say further overnight closures on the same section of motorway are planned for next week to complete the upgrade.






  1. joust says:

    adding the barrier will see a significant improvement in safety. With vehicles joining the motorway previously crossing 3 lanes of potentially highway speed traffic in the space of a few-hundred metres ahead of a fork in the motorway.

  2. Patrick davis says:

    So then, what is the potential of a similar south bound barrier from the harbour bridge through to Victoria park flyover, keeping the clip on traffic to Fanshaw st exit only.
    Anecdotal evidence would suggest safer and smoother traffic flows for southbound through traffic.
    Isn’t most f this congestion the result of last minute lane changes and arrogant queue jumpers?


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