Emergency Services Minister Murray Watt said while specific payments had not been approved, the Commonwealth would make sure assistance was provided quickly.
“The cabinet was briefed just this morning on those issues.”
The floods are the fourth time in the past 18 months that areas of Sydney and NSW have been inundated.
“We’re talking about some really important food-producing parts of Australia.”
50,000 people given evacuation orders
The weather system that drenched Sydney was expected to impact the Hunter region on Tuesday and the Mid-North Coast on Wednesday.
About 19,000 homes are without power after rising waters and damaging winds prompted energy companies to cut electricity.