The town of Gympie in southeast Queensland is preparing for its second flood in a month.
The Mary River is expected to reach 19 metres some time before 6am (AEST) on Wednesday - four metres above the flood level.
Mayor Ron Dyne told AAP around 40 or 45 businesses would probably be affected and three to four houses.
He said after the second flood in a month, townsfolk are a bit water shy.
"They're a resilient crowd but they're jack of it."
The Weather bureau said once the Mary River peaks, it should begin subsiding pretty quickly and be almost back to normal by late Thursday.
AAP reports the threat to Bundaberg has also passed.