The Queensland town of Saint George is facing a new threat, with flooding damaging a sewage treatment plant and contaminating waters.
While the town has managed to avoid widespread inundation, the plant is underwater and posing a risk to public health.
Residents had been hoping to begin to return to their homes on Wednesday, but police say a mandatory evacuation order will remain in place.
Engineers say the full extent of the problem cannot be assessed until the floodwaters recede.
The ABC reports the Balonne River has reached 13.93 metres at St George and is still rising slowly to a predicted peak of around 14m. A temporary levee is still protecting the town.