The Shoalhaven has escaped a battering from damaging winds which caused havoc in Sydney and parts of the Illawarra late yesterday.

Winds gusting up to 91 kilometres per hour brought down trees and power lines around Kiama and Wollongong with more than 700 homes blacked out at Jamberoo.

Meantime, the northbound lanes of the F6 between Helensburgh and Bulli Tops remain closed this morning as firefighters continue to battle a bushfire which has burnt out around 500 hectares.

The freeway was closed completely until around 9.30 last night with traffic banked back to Waterfall.

Vehicles are being diverted into Appin Road but motorists are warned that smoke has reduced visibility in the area.

At one stage the fire was threatening properties on Darkes Forest Road, but winds eased overnight and volunteers were able to contain the fire.