Former detective Dean Betts will oversee clean-up and rebuilding efforts in Greater Sydney, while fellow Resilience NSW director Mel Gore will take charge of operations for the state's Central Coast, Hunter Valley and mid-north coast.
"These appointments will help to ensure flood-affected communities receive support in a timely and efficient way," Emergency Services Minister Steph Cooke said on Saturday.
As flooding continues to affect the Hunter and lower Hawkesbury regions, more than 1000 government personnel are on standby to assist.
Ms Cooke said the immediate priorities were damage assessments of flooded homes and businesses, and making sure displaced residents could access emergency accommodation.
Of 2285 premises already examined, 239 have been deemed not habitable and a further 973 require repairs.
Some 37 Victorian emergency personnel were travelling to NSW on Saturday to assist with the rescue and clean-up operation, taking the total number of crew from the state to 94.
The latest deployment includes 26 members of the State Emergency Service and 11 swift water rescue specialists from Fire Rescue Victoria. Some volunteers are to be sent to the Gosford and Maitland areas.
"Our neighbouring communities in NSW are suffering from an extreme and devastating weather event, so we will of course lend a helping hand during this difficult time," Fire Rescue Victoria Commissioner Ken Block said.
On Saturday, 37,000 people remained under 35 evacuation orders, with the SES warning people to be mentally prepared as they return to inundated homes.
The easing deluge allowed some to return, but that came with dangers, Adam Jones from the SES told AAP.
"There'll be debris, their homes won't have been checked, so if it has been inundated, there could be structural issues," he said.
"The electrics might need to be looked at by an electrician. There could be mud and sewage everywhere."
Flood-affected residents returning home should wear PPE, boots, gloves and have sanitiser handy.
He also urged people to be mentally prepared as they return to properties which may have suffered significant damage.
Meanwhile, Premier Dominic Perrottet is hoping the federal government will commit to half the funding required to raise Sydney's Warragamba Dam wall.
"This is a project in the billions of dollars. It is not a simple project," he said on Friday.
Mr Perrottet said he wanted to push ahead with the initiative despite the state being warned to pull back from major infrastructure initiatives during the current economic turbulence.
Labor Leader Chris Minns said he was sceptical about raising the dam wall and wanted to see more money thrown into evacuation routes for flood-affected areas.
In the Hunter, lower Hawkesbury and Blue Mountains regions, roads remain cut in multiple towns and train services affected.
On the Hunter line, no trains are running between the Newcastle Interchange, Scone and Dungog, and many buses are diverted or missing stops.
The T1 Western and Blue Mountains train lines remain partially affected, as are the Parramatta River ferries.
Government recovery centres across Greater Sydney, the Hawkesbury-Nepean Valley and Central Coast will open in the coming days.
Some 37 local government areas across NSW remain under natural disaster declarations, while SES Commissioner Carlene York has signed "transition to recovery" handover orders for those covering Camden, Canterbury-Bankstown, Fairfield, Liverpool, Penrith and Sutherland.
