Residents in the central Queensland hub of Bundaberg have been told to leave immediately as they brace for major flooding which has triggered comparisons with a 2010 natural disaster.
Locals are preparing to leave before the community's two major bridges are shut down amid fears homes might be isolated for days.
"Your life is at risk," said a Bundaberg Regional Council warning issued on Tuesday afternoon.
More than 400 homes and businesses were under threat due to looming floodwaters, Queensland Premier David Crisafulli said in Bundaberg on Tuesday.
"This will be a challenge, but it's not a challenge that the community hasn't handled before," he said.
Door-knocking has begun and emergency alerts sent to warn locals of the imminent danger as the Burnett River threatened to peak at 7.6 metres.
It is only slightly below the 7.92m levels of 16 years earlier when homes and businesses were inundated and hundreds forced to leave the city of more than 70,000 people.
Bundaberg's Tallon and Burnett bridges were to be closed on Tuesday afternoon, leaving about 10,000 people isolated - potentially for a number of days.
"If the floods of 2010 impacted you, then you need to consider leaving immediately and finding safe haven," Bundaberg mayor Helen Blackburn said.
"We're not new to this, we've done it before.Â
"We can replace possessions. We can't replace people."
An evacuation centre has been set up at the Bundaberg Recreational Precinct with the swollen Burnett River set to reach its peak early on Wednesday morning.
"We have had rain for the last five days, so, everyone would have known that with rain, there's potential for floods," Ms Blackburn said.
"It (being isolated) is certainly something that I would hope that people are prepared for.
"They need to make sure they have clean water and we don't want them staying if they're not in a safe place."
Water rescue crews and extra emergency services including more than 30 police had been sent to the Bundaberg region in preparation, Mr Crisafulli said.
The flood-prone town of Gympie and surrounding communities were also at risk, with a major warning current for the Mary River with water still flowing downstream.
The damage was not so severe further upstream in the North Burnett, as the river peaked just short of inundating homes at Gayndah and Mundubbera.
"It's lower than previous floods," North Burnett Regional Council Mayor Les Hotz told AAP.
Almost 800 roads across Queensland have been cut by floodwaters after a tropical low left a trail of destruction, claiming about 1000 livestock.
Flooding has also hit hard in the Northern Territory.
The federal and NT governments announced on Tuesday further disaster assistance funding for Katherine, where overnight rain boosted floodwaters that forced about 700 people to seek shelter.
Hundreds of residents from the inundated NT communities of Daly River, Palumpa, Beswick and Jilkminggan were airlifted over the weekend, mostly to Darwin.
The NT capital's residents have been asked to reduce water use as authorities repair a Darwin River Dam pump station that was shut down by flooding.