A man has been rescued and taken to hospital following a water incident in Northland.

The St John's ambulance arrived at the Whangārei Marina at 9.30am today to find an elderly man face up and unconscious in the water.

The patient was given CPR and transported to Whangārei Hospital.

The police confirmed it was not a scuba-diving-related incident, however, investigations are under way to determine the cause of the incident.

Police have urged any witnesses at the scene to come forward and help with the investigations.