The river was at 1.7m at Settlement Point, upstream from Port Macquarie, Ms Collings said.
Sydney felt the storm's force on Saturday night.
Narellan in the city's southwest and Malabar in the southeast were smashed by torrential rain and 100km/h winds, which destroyed several homes.
In Sydney's east, savage winds described by locals as "mini-tornadoes" damaged an RSL club and a primary school and tore part of the roof off Fox Studios.
The SES said its focus on Sunday would be on recovery, with its main efforts divided between the mid-north coast and the storm damage in the Sydney and Illawarra.
"At the moment the weather seems to have subsided and it's the clean-up phase," an SES spokeswoman told AAP.
Flood warnings from the Bureau of Meteorology (BOM) remain in place for 15 river systems across the state.
The Colo river northwest of Sydney was predicted to rise to 10.7m on Sunday, a "near major flood level", according to the SES and BOM.
In total, about 19,000 people across NSW had been ordered to evacuate their homes, Ms Collings said.
Power supplier Ausgrid said about 10,000 homes had lost power, mainly in Sydney's north and east and on the central coast.
"Crews will be patrolling hard-hit streets making sure power lines are safe before restringing lines and restoring supply, an Ausgrid spokesman said in a statement on Sunday.
"They will focus on major cables to get larger numbers of customers back before repairing individual service wires and low voltage cables."
Earlier on Sunday, the Macleay River near Kempsey on the NSW mid-north coast peaked at 7m, about 30 centimetres below expectations.
Water was up to 1.2m deep in parts of the town, but its two main streets had not been flooded.
Grafton, which almost went under three weeks ago, was spared again after the Clarence River peaked about 1.5m below the town's levee.
Two people have died in the floods in the past two days.
On Saturday afternoon, the body of a man was found in his submerged car on a flooded road at Mylneford, about 20km northwest of Grafton.
On Friday, a 17-year-old boy died after he was swept into a drainpipe while collecting golf balls in waist-deep water in the town of Kew, near Port Macquarie.
-AAP