Thousands of homes throughout greater Western Sydney, including the Hawkesbury and Blue Mountains, are without power this afternoon as the region continues to be lashed by strong winds.
Endeavour Energy says 21,000 homes across the region are affected.
Emergency crews are working to restore power, but with strong southerly winds expected across western Sydney by around 7pm, the company predicts more outages are likely.
"This change will see winds between 70-90 kilometres per hour that are likely to cause further network damage," an Endeavour Energy statement said.
Faring worse than western Sydney is the South Coast, Southern Highlands and Illawarra, where more than 30,000 homes and businesses are without power.
"We are asking customers to please make plans according to their family circumstances as conditions worsen this afternoon," Endeavour said.
"It is expected that some customers will be without power overnight, particularly in outlying areas away from major population centres.
"Endeavour Energy's current focus is to patrol and make safe the extensive damage caused by branches hitting powerlines.
"In total, the wind today has caused over 460 electrical hazards on the network across a broad area."