The most recent fatality was a man believed to be in his 40s whose body was found near Terragon, south of Murwillumbah on Friday afternoon.
About 400 personnel across the NSW Rural Fire Service, Fire & Rescue NSW and the Australian Defence Force are joining locals to start the clean-up effort.
"The immense scale of the flooding is unprecedented and we are putting equally unprecedented resources into the significant clean-up and long-term recovery effort," Emergency Services and Resilience Minister Steph Cooke said.
Ms Cooke will also soon take on the role of Flood Recovery Minister, Premier Dominic Perrottet announced on Friday.
Concerns have been raised about the depth of the government's preparation, resourcing and response to the disastrous floods, with Mr Perrottet acknowledging on Friday it was likely mistakes were made.
Those will be identified when the government conducts its reviews and the premier has pledged to "resource every level of government to a level that will provide protection to the people of our state".
The SES has begun giving the all clear for evacuated residents to return home after Sydney dodged the bulk of the rain.
Essential Energy said on Friday it had restored power to 37,500 customers in the north of the state, with 13,500 to go.
In western Sydney, Endeavour Energy estimates it will be several days before flood-damaged electricity infrastructure can be assessed after power was turned off at more than 900 low-lying properties along the Hawkesbury, Nepean and Colo Rivers on Thursday.
The Hawkesbury River could again peak at a moderate flood level near Wisemans Ferry on Saturday afternoon.
The SES is warning the river, north-west of Sydney, could hit 3.5 metres about 1pm with the high tide.
The Bureau of Meteorology has also issued a moderate flood warning for Tuggerah Lake, north of Sydney.
The SES says moderate to major flooding is possible along the Hawkesbury and Lower Nepean Rivers from Sunday with more rain forecast.
Over the next four days parts of NSW could see up to 100mm of rain and parts of the Hunter up to 150mm with severe thunderstorms, heavy rains and damaging winds forecast, said the BoM.
"We are not past the danger period yet. The rivers are very high, fast-flowing," NSW SES Commissioner Carlene York said.
Further rain over the weekend falling in saturated catchments could cause renewed river rises in areas already devastated by flooding.
Cash management providers Prosegur and Armaguard have delivered cash to Casino, Byron Bay and other towns around northern NSW as electronic payment systems were taken out of action and ATMs ran out of notes.
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