Five people have been injured in a multiple car crash on Auckland's north-western motorway this afternoon.

Emergency services have been at the scene since about 12.15pm.

A Fire Service spokesman said six cars had been involved and five people had been injured.

He was unsure of the severity of their injuries, but confirmed some had been taken to hospital, while others had not require hospital treatment.

The crash site is on the city-bound side of the motorway between St Lukes and the Newton Road off-ramp.

Traffic in the area is building as a result of the accident and motorists are being warned to use alternative routes or to expect delays.