Emergency services are in attendance at a crash on State Highway 20 near Manukau.
The crash, involving a motorcyclist, was reported to Police at 1.11pm.
Initial indications are one person has sustained critical injuries.
Two westbound lanes are blocked near the Great South Road overbridge.
Motorists are advised to expect delays and seek alternative routes.
The Serious Crash Unit has been notified.
ENDS.
Frankie Le Roy/NZ Police.