Thousands of NSW residents are bracing for flash flooding with heavy rain and thunderstorms to hit many parts of the state.
Ninety-eight flood warnings are current, with the SES performing 21 rescues and answering hundreds of calls for assistance overnight.
The focus of the crisis continues to be in the state's far northeast and southeast, close to the Victorian border.
NSW Emergency Services Minister Steph Cooke said large parts of the state, including the inland and west, were in for a "difficult few days".
Emergency services are preparing for a busy weekend as the wild weather arrives, with volunteers handing out 30,000 sandbags a day.
"We are quite literally sandbagging the state," Ms Cooke said on Saturday.
SES Commissioner Carlene York said flash flooding and hail could be made worse by heavy winds which could easily uproot trees in saturated areas.
"It's already extremely busy and we're expecting this next 24 to 48 hours to see more requests for assistance," she said.
In the north, emergency warnings are in place for Moree, Narrabri and the hamlet of Terry Hie Hie, while an evacuation order is current for Moama in the southern borderlands.
The Bureau of Meteorology warns the big wet will likely continue, with widespread showers and thunderstorms forecast for eastern NSW, including Sydney, resulting in flash flooding for many regions.
The bureau says the northeast is an area of concern as a trough and possible low-pressure system develops off the coast, bringing heavy rain to the Northern Rivers, including Lismore and Byron Bay.
Hazards, preparation and response manager Jane Golding said floods and rain will impact "quite a significant portion of NSW".
A 1955 flood record is expected to be broken at Moree, while other parts of the state will see levels close to peaks reached in the past two years of flooding.
A woman with a pre-existing medical condition was airlifted to hospital in Tamworth late on Friday by the Westpac Rescue Helicopter after becoming isolated by floodwater on a property at Narrabri.
The same chopper was called to a Northern Tablelands farm west of Glen Innes on Friday after a man trying to drive a tractor through floodwater became stranded when the engine stalled.
He was dragged approximately 200 metres to dry land by onlookers before being treated by paramedics for exposure and hypothermia.
Two hundred defence personnel are being deployed in Dubbo, Moree and the Northern Rivers, with two more Australian Defence Force helicopters coming online ready for night rescues.
Specialist swift-water rescue crews have also been dispatched to the flood-threatened north while others are in place at Dubbo.
Still more Fire and Rescue teams are operational at Moama, Barham, Warren and Moree, while pilotless aircraft and drones are being used to deliver situation reports on the Murray River and in the New England region.
The bureau has forecast rain and storms on Saturday further south, including Sydney, where it predicts a thunderstorm will bring heavy falls causing flash flooding.
Residents in the city's west are expected to bear the brunt, with flooding tipped on the Hawkesbury and Nepean rivers.
The bureau said there would be some brief reprieve from the rain towards the middle of next week but flooding would continue.
An additional 12 local government areas were added to the state's natural disaster declaration list, with residents in Albury, Berrigan, Carrathool, Cobar, Federation, Griffith, Hay, Leeton, Murray River, Murrumbidgee, Narrandera and Wagga Wagga now able to claim financial aid.
