A 17-year-old girl was airlifted from a small island near Waiheke Island after suffering an allergic reaction this morning.

St John were alerted to the incident on Motuihe Island just after 10am, a St John spokesman said.

The girl had suffered a moderate allergic reaction. The spokesman was unsure what had caused the reaction.

Westpac Rescue Helicopter attended the incident and flew the girl to Auckland City Hospital emergency department in moderate condition.