The Trustpower TECT Rescue Helicopter was dispatched to Waihi last night at 8:45pm.
A 32-year-old man suffered a medical event which required immediate hospital care.
St John paramedics were able to stabilise the patient before he was flown to Waikato hospital for further treatment.
The flight was conducted under night vision goggles and the helicopter was called due to the nature of the medical event and distance by road to the required hospital.