Warnings remain in place as NSW communities seek to return home after flood

The flood threat in some NSW towns is easing as waters recede but authorities say it's still too soon for many people to return home.

NSW residents returning to flood-hit homes have been urged to take care and watch for damage. Source: AAP / Supplied

Dozens of evacuation warnings remain in place along the Hawkesbury River northwest of Sydney over an ongoing flood threat, while some people have been given the green light to return home.

Late on Saturday night residents in parts of Wisemans Ferry were told they could be isolated without power, water or other essentials as floodwaters at Sackville peaked overnight.

Some 36 flood alerts remain along the river system, with emergency warnings in 12 communities flagging it is still not safe to return.

However, the threat has started to ease in some areas, with residents in parts of Camden and Ellis Lane, about 65km southwest of Sydney, allowed home on Saturday.

"You should take care when returning to the area as flood damage can be widespread," the NSW State Emergency Service warned.

The service will begin to survey the damage to communities as waters recede, with possible impacts to infrastructure including roads.

Heavy rainfall earlier in the week soaked Sydney and other parts of the state, causing the Warragamba dam to spill for the third time in three months and threatening communities downstream in the Hawkesbury-Nepean Valley.

Swelling rivers brought moderate flooding to North Richmond, peaking at 10.13m after 8am on Saturday, before waters began falling and is expected to be below moderate flood level on Sunday, the Bureau of Meteorology said.

Warragamba dam outflows have slowed, but WaterNSW chief executive Andrew George said it may take a few days to return to normal.

About 600 residents in low-lying areas of the Hawkesbury-Nepean Valley were ordered to evacuate on Friday night.

The NSW State Emergency Service conducted more than a dozen rescues during the latest flooding. Source: AAP / Dean Lewins

The immediate threat of more damaging rainfall has eased, with the bureau not forecasting any further significant falls over the next few days.

"Our priority is to get people back to normal as soon as possible," NSW SES acting commissioner Deb Platz said.

But she warned residents to remain wary around the Hawkesbury Nepean catchment.

"We do not need to see significant rain to bring riverine and flash flooding," she said.

"As we have saturated catchments and full dams the rivers can rise very quickly."