A person is in a critical condition in Middlemore Hospital after a car crash south of Auckland this afternoon.

Emergency crews were called to Hunua Rd just after 4.30pm in response to reports of a single-car accident.

St John said two ambulances were sent to the scene and that a person - whose age and gender are yet to be released - had suffered critical injuries.

A spokeswoman for the Fire Service said shortly before 6pm that a fire crew remained at the scene to help clear the site and control traffic.