The crash that snarled up traffic on the motorway is now clear - but there is still heavy congestion.

A State Highway 1 crash blocked two lanes and seriously injured a person around 2.30pm this afternoon.

The collision occurred between a motorcycle and a vehicle in the northbound lanes on the southern motorway, prior to Takanini.

A temporarily lane was opened through roadworks to allow traffic to pass through.

Advertisement

The lanes have now been cleared but northbound traffic is congested to Ramarama and southbound traffic is heavy from Princes St.

Motorists were advised to be patient.

There was also a crash affecting southbound traffic at the Hill Rd off-ramp. The crash has been cleared but traffic was backed up to Highbrook.

The NZ Transport Agency is expecting heavy traffic and delays as the afternoon peak period builds. It thanks motorists for their patience and advises them to delay their journeys if at all possible.