The package is the largest ever allocated for a natural disaster and bring total preparation and recovery funding to $178 million.
Prime Minister Anthony Albanese said the river communities should know the Commonwealth was standing by them ready to help.
"This assistance will provide invaluable support to residents, farmers and businesses to recover from this flooding disaster," Mr Albanese said in a statement on Tuesday.
"The quicker we recover, the sooner we can begin investing in mitigation to lessen the impact of events like this in the future."
The package includes $10 million to assess damage to homes, $9.3 million for small business recovery grants, $45.9 million for primary producer grants and $60 million for waste management and other clean-up work.
There will also be $800,000 to assist with the clean-up of any large-scale fish kills and $250,000 for legal assistance for affected people and businesses.
Premier Peter Malinauskas said while river levels were starting to fall close to the SA border, communities downstream were still bracing for the peak.
"This event is going to be with us for some time. We're still witnessing these floodwaters wreak devastation along the river," he said.
"Our river communities have been united, resourceful and courageous through this event. But we know we have a significant clean-up ahead.
"Getting to work quickly will be vitally important for communities to recover and thrive."
The flooding has so far impacted about 3400 properties, including nearly 400 primary residences.
It has also closed 119 roads across river communities with nine ferries shut down.
The Murray is expected to peak at Waikerie and Morgan between now and January 7 and at Blanchetown, Swan Reach and Mannum between January 4 and 13.
This week, the continued surge breached or inundated a string of agricultural levees including those at Mypolonga, Toora, Mobilong, Cowirra, Wall Flat, Long Island and Long Flat.
The State Emergency Service said more issues with levees could be expected as peak flows moved down the river.
Chief Officer Chris Beattie said authorities were also keeping a close eye on the release of more water from the Menindee Lakes in NSW which would eventually flow into the Murray.
He said that water would start to have an impact in SA in early February but was not a great concern at this stage.
18°C