Rescue underway after Sydney cliff fall

A rescue operation is underway to extricate a man, believed to be aged in his 70s, who has fallen off a cliff on Sydney's north shore.

A man believed to be aged in his 70s has been seriously injured after plunging about 25m down a cliff on Sydney's upper north shore.

A delicate rescue operation is underway to rescue the man near Acron Road in St Ives after the alarm was raised about 4pm on Monday.

The man is understood to have suffered serious head and chest injuries.