Western Sydney could be in for minor flooding after Warragamba Dam spilled over following a weekend of heavy rain.
A State Emergency Service (SES) spokeswoman says the spillover occurred about 3.30am (AEDT) and could cause flooding in local areas.
"Penrith could be affected and the Richmond areas today on the Hawkesbury Nepean River," she said.
Minor flooding could disrupt local ferry services and close low roads and bridges.
As swollen creeks and rivers start to recede across the state, the SES says 26,000 people remain stranded by floodwaters in the north but the focus now is shifting to recovery and resupply.
Crews from the SES, NSW Rural Fire Service and Fire and Rescue NSW are concentrating on the Sydney suburbs of Malabar and Narellan, and Kiama on the south coast, which were worst-affected by storm damage over the weekend.
In Kiama, three houses were destroyed and seven others badly damaged, while St Andrew's Primary school at Malabar will be closed on Monday for safety checks.
Meanwhile Ausgrid crews are working to restore power to about 500 homes and businesses on the Central Coast, about 100 in Sydney and more than 500 around Kiama and Bowral.
At its peak over the weekend, more than 6000 homes and businesses on the Central Coast were without power as trees and debris hit powerlines.
Flooding at Putty Road in Colo, from the Colo River which peaked on Sunday, has closed some local roads, the SES said.
Flooding is also expected to affect low-lying farmland and local roads near the rivers and their tributaries and a number of caravan parks on the Colo River and lower Hawkesbury from Lower Portland.
"Farmers should watch the weather and be ready to move pumps, other equipment and livestock away from rising waters," the SES said in a statement.
The clean-up of asbestos debris is continuing at the Malabar RSL in Sydney's east.
Savage gusts extensively damaged the club's roof on the weekend, sending sheets of asbestos flying onto nearby homes and roads.
An SES spokeswoman says two streets near the club have been closed off.
But there's better news up the coast at Kempsey, where the SES has given the all-clear for the CBD with the exception of some properties.
So far there have been 85 flood rescues across NSW, mainly from vehicles.