NSW emergency services have responded to more than 700 calls for help and conducted 13 flood rescues over the past 48 hours as rain batters the state's south coast.
Up to 200mm of rainfall hit a number of towns including Moruya, Nowra and Captains Flat over the past 24 hours, and the bad weather is likely to linger in NSW until Tuesday.
More than 20 homes at Broughton Vale near Berry were also cut off by floodwater.
Flood warnings associated with the low pressure system have been issued for the Shoalhaven, St Georges Basin, Deua, Moruya and Bega rivers, while flooding along the Snowy River and the Queanbeyan River has not been ruled out.
Severe weather warnings have been issued on Sunday for a large stretch of the NSW coast from Moruya to Kempsey, taking in Wollongong, Sydney and Newcastle. Heavy rainfall, damaging winds and very heavy surf are expected.
"Residents are waking up to a changing landscape," NSW State Emergency Service deputy incident controller Allan Budziarski said in a statement on Sunday.
"We remind everyone, whether you are a local or just passing through, never walk, ride, drive or play in floodwaters.
"The rain is expected to remain around until Tuesday but we urge drivers, especially those travelling along south coast NSW, to take care while on the roads, drive to the conditions."
Disaster assistance has been made available to those impacted in the local government areas of Bega Valley, Eurobodalla, Kiama, Shellharbour, Shoalhaven and Newcastle.
The NSW SES encourages those dealing with the heavy rainfall to move vehicles under cover, secure loose items around their homes and keep at least eight metres away from fallen power lines.
