Flooding threat eases in Sydney's west

Residents returning to flooded homes in NSW have been urged to proceed with caution as the threat of rising waters eases in western Sydney.

Flooding is still a concern for some western areas as the Warragamba Dam spills and Hawkesbury and Nepean rivers rise.

However, the spillover from Warragamba Dam is expected to be less than previously forecast.

More than 300 residents in Sussex Inlet and St George's Basin on the state's coast began returning to their homes on Thursday after being evacuated the day before.

The SES has attended more than 1700 calls for help since the storm began on Monday, first hitting central NSW and Sydney, before sweeping south to the Illawarra and south coast regions.

Ninety flood rescues have been carried out in that time.

People have been warned to check the credentials of tradespeople during the clean-up period and that household electrical items could be dangerous following the floods.

"Before turning on your utilities make sure you get them checked by qualified electricians," NSW SES spokesman Phil Campbell told AAP.

"Be weary of your appliances. Your fridge might have short-circuited; you don't know the damage."

The SES advises people to thoroughly disinfect their homes as sewerage could have overflowed into floodwaters and could be carrying diseases.

Residents in the Nepean-Hawkesbury valley have been told to prepare for minor flooding on Thursday night, especially in the North Richmond area.

The weather bureau predicts a slight chance of showers on Thursday night and has issued a warning for strong winds along the coast between Illawarra and the Hunter region on Friday.