Australia's flood crisis deepened Monday, with hundreds more forced to flee their homes in the rich agricultural land of the southeast and a second death as a car was swept off the road in Queensland.

Days of heavy rain have hammered the eastern states of Queensland, New South Wales and Victoria, swelling rivers, flooding farmland and forcing the closure of bridges and roads.

Emergency officials said Monday they were concerned about the Riverina region in southwest New South Wales, where the Murrumbidgee river has burst its banks in some areas and inundated homes near Wagga Wagga.

"It's still a very dangerous situation right across the region," State Emergency Service spokesman James McTavish said of the Wagga Wagga area where more than 1,000 people have been ordered to evacuate their homes.

Across New South Wales, more than 5,000 people have been ordered to evacuate, with another 2,000 stranded.

In Wagga Wagga, residents said there was an eerie calm, as floodwaters surged under blue skies and sunshine.

"It's so strange, it's a beautiful day in Wagga, so we're just sitting around, drinking tea and waiting for the river to quietly engulf the floodplain," local man Tim Kurylowicz told AFP.

"What was a relatively small river two days ago is like an endlessly wide lake, with treetops swishing amongst the water," he added.

"It's quite serene to look at, but you can tell it is also moving incredibly fast."

Kurylowicz said his neighbourhood had been an "island" by the time he evacuated early Monday to an unaffected part of town and it was forecast to be completely engulfed by water before sunrise on Tuesday.

Authorities are bracing for a 10.6-metre flood peak on Tuesday morning and hope the town's 11-metre levee will spare the central business area from inundation.

Downstream at Gundagai, about 30 homes and businesses have been flooded, with the water surpassing levels reached during a 2010 flood.

Authorities again warned people against driving their cars through floodwaters after more than 30 rescues overnight, including that of two adults and three children who had been trapped in a car in Wagga Wagga.

One man died at Araluen in southern New South Wales at the weekend after being washed downstream as he attempted to drive through floodwaters. His two companions were rescued, one reportedly clinging to a tree.

The toll rose Monday after a man died when his car was swept off a road in heavy flooding in the southeast Queensland town of Glenwood, near Gympie.

Police said they had been unable to confirm a report that a second vehicle was also swept away.

Several small towns in the north of Victoria state were bracing for waters to peak.