The worst flooding in a century in the state of Queensland has caused water levels to reach 9.1 metres above normal levels in some areas.
Some 22 towns and cities have been swamped in the area known for cattle and fruit farming.
Police in Queensland said that as many as 10 people have drowned since heavy rains began in late November.
The town of Rockhampton is undergoing an evacuation after the area’s main highway and airport runways were flooded.
Supermarkets have been running out of items as residents stock up on food and bottled water, forcing military airlifts to provide additional aid.
Residents say that animals have followed the high waters, as towns have been plagued by mice, frogs and snakes.
The next expected threat is giant saltwater crocodiles, which are being washed into urban areas as they seek higher ground.
Australian Prime Minister Julia Gillard says damages may reach hundreds of millions of dollars.
Emergency loans have been extended to those affected to begin farm clean-ups and to get businesses running.