UPDATED 9.30pm: The scheduled hazard reduction burn at North Head today jumped containment lines.
The planned operation is understood to have caused spot fires around 2.00pm outside the area of containment, resulting in danger to the Big Brother House and evacuation of the Quarantine Station.
The fire ground is under the control of NSW National Parks and Wildlife Service, assisted by Fire & Rescue NSW and NSW Rural Fire Service, and supported by water bombing aircraft.
A Fire & Rescue NSW spokesperson said the fire did present some danger to structures but conditions were favourable for bringing the fire under control and sufficient crews were in place to safely defend buildings.
The location and terrain presented firefighters with some difficulty attacking the fire which was being pushed by winds in a southerly direction, towards the cliffs.
The spokesperson said that although the fire was not under control at around 4.30pm, the threat to life and property was minimal and they would adopt a containment strategy.
NSW Police advised people to avoid the area, with roads and tracks closed to motorists and pedestrians.
This is the second fire in a month at North Head to result in an evacuation of the Quarantine Station.
As of 9.30pm, the fire continued to burn steadily towards the southern end of North Head in the direction of the artillery lookout and was being controlled by firefighters.
The image below was taken around this time, looking across from Fairlight.
Images: Fire & Rescue NSW, Lee Furlong.