The man and woman, both in their early 20s, were walking in bushland near Quarter Sessions Road in the suburb of Westleigh at around 11.30pm yesterday after a party.
Suddenly the pair fell approximately 20m down a cliff.

Emergency services were notified, and a multi-agency response ensued, with Ku-ring-gai Police, Police Rescue, NSW Ambulance, and Fire and Rescue NSW all working together to help rescue the pair.
After six hours emergency services were finally able to winch the two off the cliff side at around 4.30am.
The man was treated at the scene for head and body injuries.
While the woman was treated for a leg injury.
The pair was then flown to the Royal North Shore Hospital for further medical help.