Residents at Ipswich, west of Brisbane, have been told to consider moving to higher ground after torrential rain across parts of Queensland.
The south and southeast have had extraordinary rain over the past 24 hours, sparking the rescue of five people caught up in flood waters.
The highest falls were in the Sunshine Coast hinterland, where falls of more than 200mm were recorded.
Very heavy rain has also lashed Brisbane, with falls of up to 130mm in the 24 hours since 9am on Thursday.
On the Gold Coast, about 20,000 people lost power but all bar 100 have since had supply restored.
The rain has eased but the effects are now being felt in river catchments west of Brisbane.
Authorities have warned residents in low-lying areas of Ipswich, Harrisville, Amberley, Laidley and Gatton to prepare for the possibility of flooding.
Queensland Fire and Emergency Services South Eastern Regional Director Steve Waddell said people should consider if they needed to move to higher ground.
"If you are told to evacuate, act quickly on the advice provided and take your emergency kit," Mr Waddell said in a statement on Friday.
"Ensure you pack light and that you and your family are wearing strong shoes and suitable clothing. Lock your home and take the recommended evacuation routes for your area."
The Bremer River is expected to reach minor flood levels at Ipswich by about midday.
"For Ipswich, the level we're predicting doesn't cause any significant problems," Bureau of Meteorology hydrologist Andy Barnes told the ABC.
He said a flood peak of seven metres was expected at Laidley, in the Lockyer Valley, by mid to late morning.
He wasn't sure whether a seven metre peak would do any damage, but that is lower than levels seen about a year ago, when some flood damage occurred.
No flooding is expected to result along the Brisbane River, which is fed by the Bremer River, downstream of Wivenhoe dam.
The wild weather sparked numerous swift-water rescues.
One man was saved from the roof of his car near Gympie and another was plucked from a tree near Aratula, east of Cunninghams Gap.
A couple was also rescued from the roof of a caravan at Rosewood, west of Ipswich, and a woman was helped from the roof of her car at Gatton in the Lockyer Valley.
The bureau says Queensland's wild weather isn't over yet.
Severe thunderstorms packing wind gusts of up to 125km/h are expected to hit parts of the Fraser Coast from Friday morning, including Fraser Island, Hervey Bay, Heron Island and possibly Lady Elliot Island.
Ipswich Mayor Paul Pisasale said residents were still haunted by past flooding and low-lying areas were at risk.
"As you know, we as a city become a little bit nervous because we got flooded in 2011, 2013 and we don't want to make it 2014," he told AAP.
However, he said the flood threat did not look as bad as previous years, with the Bremer River expected to peak at 8m as opposed to 19m in 2011.
He said the biggest cause for concern was motorists not driving to wet weather conditions and there had already been several crashes in the region.
Council would keep residents updated on developments via websites and social media, he said.
Meanwhile, Gympie Mayor Ron Dyne said the local roads were flooded and the Kidd Bridge would go under about 6pm (AEST) when heavy downpours on the Sunshine Coast made their way into the Mary River.
Mr Dyne said floods were "standard fare" in Gympie and locals were already making preparations.
"We're well-versed here with floods unfortunately. We're trying to change that reputation, but we've dealt with this all before," he said.
