Surf lifeguards and a rescue team have pulled an unconscious person from the water near Gisborne's Sponge Bay.
Two inflatable boats and a rescue helicopter responded to the emergency at Tuamotu Island on Tuesday morning, Surf Life Saving New Zealand said.
The Eastland Rescue Helicopter winched a medic to the person and surf lifeguards provided help.
St John said one patient in a moderate condition was airlifted to Gisborne Hospital.
Two others were assessed at the scene and had minor injuries.