Queensland authorities say they are increasingly worried about the spread of disease and supplying food to thousands of people in flooded communities.
They say drinking water in many towns has been contaminated by sewage, chemicals and rubbish, and muddy water.
Thousands of people have been evacuated - or are facing evacuation - across the state - including the cities of Rockhampton and Bundaberg, the town of Emerald and the townships of Condamine and Theodore.
Bruce Grady from Emergency Management Queensland says there is concern about the possible spread of water-borne diseases.
He says the organisation is talking to councils in the area on Thursday and if bottled water and water purification are needed that will form part of the response.
Representatives from the state's independent and major supermarkets are talking with authorities about how to open new supply routes.
Mr Grady says one option could be to send food to the state's north and then try to move it inland.
In the meantime supermarkets are trying to stockpile essentials in flood-affected areas.
Hundreds face evacuation
More than 1000 people have already been evacuated reports the ABC.
Up to 80% of Emerald, a town of 11,000 residents in central Queensland, is expected to be inundated when the Nogoa River peaks at a predicted 16.2 metres on Friday.
Queensland's Premier Anna Bligh, who has arrived there, says more military helicopters will be sent to flood-affected areas and a Black Hawk will be stationed at the airport for the next few days.
In the city of Bundaberg, more than 400 homes were evacuated on Thursday as the Burnett River peaked at 7.9 metres on Thursday morning.
The BBC reports the previous high water record for the Burnett River was about 7.2 metres in 1954.
Some houses are nearly submerged and whole communities are isolated.
All 100 residents of the town of Condamine are being evacuated and the Condamine River is expected to peak at more than 15 metres.
No-one is left in the town of Theodore, west of Bundaberg, after the first complete evacuation of a town in Queensland's history.
In Rockhampton emergency crews have had more than 100 calls as the Fitzroy River rises and it's expected to peak at 9.4 metres early next week, a metre higher than first predicted.
The cost of the damage is expected to top AU$1 billion, including big losses of sunflower and cotton crops.