Wind gusts of up to 100km/h throughout the week left more than 100,000 Sydney customers without power, and 40,000 were still without electricity on Saturday morning, Ausgrid said.
Another 12,000 customers were without power in Newcastle and the Hunter regions, along with 8000 in Port Stephens.
Rain delayed play during a Big Bash League match at the SCG. (Mark Evans/AAP PHOTOS)
The NSW State Emergency Service received 2825 calls for help on Friday night, including four flood rescues.
Warnings are in place for communities and campers northwest of Newcastle, downstream of the Chichester Dam.
"We do currently have some communities and some locations that are becoming isolated, and the warnings reflect that, and we're very closely engaged with the local communities," SES commissioner Michael Wassing told reporters on Saturday.
"Most of our other calls are associated with significant storming impact around the Sydney area, particularly North Sydney."
Two people were injured when a large tree fell at Hyde Park in central Sydney. (Steven Saphore/AAP PHOTOS)
On Friday afternoon at least two people were injured when a large fig tree in Hyde Park crashed to the ground across a footpath and onto a busy street.
Two people suffering minor injuries were transported to the nearby St Vincent's Hospital for treatment, a NSW Ambulance spokesperson said.
Earlier in the week a man in his 80s was killed when a tree fell on his car overnight in the state's central west.
Federal Emergency Management Minister Jenny McAllister declared the wild weather a natural disaster, opening up disaster payments for families and businesses affected.
"The assistance activated today will ensure communities can access essential supplies and accommodation and ensure councils can start clean up and repairs," Minister McAllister said.
"This is a time when individuals need to think about their own risks and listen to advice."
Emergency Management Minister Jenny McAllister has declared a natural disaster. (Mick Tsikas/AAP PHOTOS)
Heavy rainfall and damaging winds are set to continue on Saturday morning but ease off in the afternoon, according to the Bureau of Meteorology.
Rainfalls up to 120mm could fall in alpine areas across NSW.
Hazardous surf warnings will remain in place for the Sydney and Illawarra coasts.
In Western Australia, a tropical low is likely to from north of Pilbara, with a high chance of becoming a tropical cyclone.
Damaging winds may develop on coastal and island communities between De Grey and Dampier from early Sunday, extending to Exmouth on Sunday night.
While the expected cyclone will move offshore before it develops, large waves could cause minor flooding between De Grey and Exmouth.
