Critical injuries in State Highway 20 crash blocking northbound lane before Coronation Rd

Delays were expected.

Motorway traffic can be seen building up northbound because of the blockage. Photo / NZTA

Traffic could be seen building in lanes past the Bader Drive overbridge, with the backlog extending 5.5km to Puhinui Rd.

Police said two northbound lanes were blocked before the Walmsley Rd overbridge and traffic was building.

NZTA said: “Consider using SH1 for northbound travel.”

An NZTA photo showed emergency services at the crash, with a vehicle lodged close to a road barrier.

One person has sustained critical injuries in a crash on State Highway 20 near Māngere.

Photos of the incident seen by the Herald show a small red car parked behind a campervan, which has a Hato Hone St John ambulance parked beside it.

Google Maps shows the traffic stretching back past Wiri, about 7km from the crash site.

A spokesman for Auckland Transport confirmed no public transport services are being impacted by the incident.

Police and NZTA have advised the crash on State Highway 20 near Māngere will cause delays. Photo / Google