A couple of people were being tested for possible flood-related infections, Queensland Premier Anna Bligh said on Sunday, reminding of the risks of a possible infectious breakout in the wake of the flood.

Bligh said the suspected cases occurred in the southern Queensland town of Theodore and the tests were precautionary.

She said dead animals, rotten food and broken chemical bottles had been found among the debris being cleaned up after the floods, warning that people to be careful when cleaning up.

Bligh also noted that there's no absolute confirmed evidence that it has anything to do with floodwaters. " We are waiting on tests on what they may be suffering from," Bligh told reporters.

As a preventative measure, medical staff were in place to offer free tetanus injections for volunteers. Brisbane Mayor Campbell Newman said free vaccinations were available to all volunteers because of the risk of diseases that were harbored in floodwaters. He said about 14 trained staff had issued more than 600 vaccinations across the four volunteer meeting points.

In inundated communities of Brisbane, many houses remained deep in catchment which began to ferment, diffusing smelly air.

"This water is toxic and if you have a cut or a scratch and this water gets into it then you are at serious risk of infection, " Bligh said.

She also said there is never too much stress upon danger associated with the massive clean-up and the need for volunteers to wear protective clothing and to be vaccinated against tetanus.