Residents in northern New South Wales and along the Victorian border are seeing the impacts of the dangerous weather system bearing down on Australia's east coast as rivers break their banks.
Multiple evacuation orders are in place across the two states but fears for Echuca in northern Victoria, Moama in southern NSW, and Moree in northern NSW are at a high.
Around 4000 people have been told to leave their homes in Moree.
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The NSW SES said major flood levels have been reached on the Mehi and Gwydir rivers.
NSW Emergency Minister Steph Cooke warned the floods inundating Moree will be record-breaking.
"In Moree, a second peak will come through the community and will come very close to the February 1955 level and even if it doesn't it will be significant flooding through that region," she said.
"Moree has two flood peaks, the first is there now and the level is higher than the March 2021 level and the second flood peak is expected to be higher again, somewhere between last year and the levels seen in 1955 which is the highest we have on record," meteorologist Jane Golding said.
Evacuation centres have been set up at the Moree PCYC on Boston Street.
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Cooke has delivered devastating news for flood-weary residents in northern NSW as Lismore is expected to see rising floodwaters again.
"The Bureau of Meteorology is predicting potentially major flooding at Lismore," she said.
Golding said the low-pressure system off the coast of south-east Queensland will bring heavy rainfall to the Northern Rivers.
"We are expecting a significant rain event to effect the Northern Rivers tomorrow and flooding following tomorrow and Monday," she said.
Golding warned there will be rainfall totals of above 150mm which will bring life-threatening flash flooding over the coming days.
Cooke said there isn't a "single part" of NSW that emergency services aren't concerned about.
Floodwaters finally hit NSW-Victoria border towns
Meanwhile on the NSW and Victoria border, an evacuation order has been issued for Echuca as the Murray River finally breaks its banks.
"The Murray River is at 94.77 metres AHD as it continues to rise and is expected to reach 95 to 95.2 metres AHD Sunday into Monday," VICSES Chief Operations Officer Tim Wiebusch said.
"If you don't wish to be isolated our strongest message is evacuate now," Wiebusch said.
Barmah near Echuca has also been told it is too late to leave as days of flood warnings come to fruition for exhausted residents.
At Moama on the NSW side of the border, Cooke warned floodwaters will peak on Tuesday.
"The latest and best advice is the river will peak on Tuesday and is likely to see exceed 1993 levels," Cooke said.
The Murray River Council mayor Chris Bilkey said earlier the region is hoping the river doesn't rise much more.
"The river has come up three, four or five inches overnight but we're confident the levee bank around the town is going to survive," Bilkey said.
"We're buckling down for another week of really high water here."
There are concerns for towns downstream along the Murray River in the coming days as floodwaters continue to plague the two states.
"We will see those waters flow downstream in the coming days where we will see major flooding," Wiebusch said.
Kerang, in northern Victoria, has been told it's too late to leave as floodwaters inundate the town.
Wiebusch said the Loddon River is currently at 74 metres AHD and is expected to peak today at 78 metres AHD.
"Kerang is largely isolated at the moment with one road out, it is expected to close as we reach the peak today," he said.
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https://twitter.com/vicemergency/status/1583624895313117184
In NSW, more than 400 calls for help were received overnight while 21 flood rescues were carried out.
While in Victoria, there were 70 calls for help overnight and several flood rescues.
Residents are advised to keep across BoM's warnings as the system bears down. NSW warnings can be viewed here, Victoria here, and Queensland here.