Police have closed McKell Avenue at Waterfall after a fatal motorbike accident.
A motorcyclist crashed while riding through the Royal National Park and was pronounced dead at the scene.
Paramedics went to the scene but could not help the rider.
Authorities have not yet released the identity, age or gender of the person involved.
A police spokeswoman said no other vehicles appeared to be involved in the incident.
She said people should avoid the area.
‘‘Emergency services remain on scene and the road remains closed in both directions Princes Highway and Sir Bertram Stevens Drive,’’ she said.
‘‘Police are urging motorists to avoid the area, expect significant delays and use alternate routes.’’