Sydney households to remain without power into weekend

Cyclone-like damage to Ausgrid's electricity network caused by severe storms could see some Sydney households remain without power into the weekend.

The utility company on Thursday said customers in the hardest-hit areas in Sydney's north should prepare to be without power until Sunday, and consider relocating if possible.

About 13,000 customers remained without electricity on Thursday evening, Ausgrid said.Impacted areas include parts of Roseville, Gordon, Pymble, Chatswood, Willoughby, Frenchs Forest, Belrose and Mosman

"This is some of the worst damage we have seen in a concentrated area and is similar to what you would expect to see after a cyclone," Ausgrid chief operating officer Trevor Armstrong said in a statement earlier on Thursday.

"We have hundreds of people working hard to make hazards safe and rebuilding sections of the network from the ground up and unfortunately this takes time."

"The devastation is on par with damage from a cyclone and the network is being rebuilt from the ground up in the hardest hit areas," the company later reiterated in a further statement.

Ausgrid warned many powerlines were still down and anyone who saw them should stay at least eight metres away.

There have been more than 1800 hazards on the network, it said.NSW was a "state of extremes" on Tuesday as severe storms downed trees and powerlines in Sydney, snow fell in Thredbo while other parts of the state sweltered.

At the height of the storms, 52,000 customers were without electricity.