A fire that threatened Sydney's landmark Barrenjoey lighthouse may have been deliberately lit, with no other obvious cause identified.
After fire broke out on Barrenjoey Head at Palm Beach on Saturday, fire crews managed to save the historic lighthouse that features on the television soap Home and Away.
But the blaze burned through 17 hectares of bushland and damaged a nearby cottage.
NSW Rural Fire Service Commissioner Shane Fitzsimmons said investigations into the fire were ongoing but the lack of an apparent cause had led the service to suspect someone may have deliberately lit it.
"At this stage one can only be suspicious," he told reporters at the official launch on Monday of the NSW bushfire season.
"We still have the fire investigation unit having a good look at that fire but in the absence of any natural cause such as lightning or a clashing power line ... we are treating that one as suspicious."
