A 52-year-old Australian cyclist who crashed on Whangamoa Saddle suffered serious chest and shoulder injuries in the fall.
St John team manager Gary Tobin said the woman lost control and landed heavily and awkwardly as she cycled down the hill.
He said the woman could have been travelling at 40kmh when she crashed on the Hira side of the saddle.
The woman was treated by St John ambulance crew and the intensive care paramedic on the Nelson Marlborough Rescue Helicopter.
She was flown to Nelson Hospital in a serious condition this afternoon.