A bus load of school children has been rescued from flash flooding in Brisbane as drenching rain buffets south-east Queensland.

A swift water rescue crew retrieved the 16 children after a bus became stranded in flash flooding at Acacia Ridge on the city's southside.

Water was rising in Learoyd Street around the bus but the students were pulled to safety within about an hour.

Queensland Fire and Rescue Service spokesman Andrew Sturgess says they had a lucky escape.

"Certainly a potentially dangerous situation," he said.

"It was just fortunate the water stopped rising at that time otherwise they would have been trapped.

"It's a message that we want to get out there - if it's flooded, forget it."

Emergency Management Queensland is urging residents to prepare for flash flooding with more heavy rain expected in the state's south-east.

Falls of up to 200mm are forecast for some areas.

EMQ spokesman Bruce Grady says the slow-moving system is nowhere near as severe as ex-tropical cyclone Oswald last month.

"We have got a very different weather pattern at the moment," he said.

"We are not seeing the same amount of rain - we are certainly not seeing the same level of wind from this event, so a very different set of circumstances.

"People just need to be alert to what is possible."

Deluge continues

A motorist had to be rescued from the corner of James and Kitchener streets in Toowoomba. ( ABC: Arlie Felton-Taylor )

It has been a hectic time for emergency crews as heavy rain drenches south-east Queensland, with more to come.

Up to 90 millimetres of rain has fallen across parts of Caboolture and the Sunshine Coast in the last 24 hours and more than 60 millimetres across Logan and the Gold Coast.

Brisbane's CBD has been spared most of the heavy falls but the weather bureau says a reprieve from the extreme weather is not expected until the end of the week.

Emergency crews have rescued a number of motorists from flooded roads, while dozens of traffic accidents have been reported.

A number of roads have been closed due to flash flooding in Brisbane's south-west, with landslips reported north-east of the city at Mount Mee.

The Brisbane City Council has opened four centres with sandbags for residents in low-lying areas.

At least one school on the Gold Coast hinterland has been closed because of flooding.

The Darling Downs and the Granite Belt have also been included on the list of regions to prepare for extreme weather.

A swift water rescue crew were called to save a person who was trapped in their car at Toowoomba.

Dam releases

Water is being released from Wivenhoe and North Pine dams in south-east Queensland as a precaution.

Earlier today Wivenhoe was at 88 per cent capacity and North Pine was at 95 per cent.

Seqwater spokesman Mike Foster said releases could be stepped up.

"That will really depend on the volume of the falls over the next couple of days," he said.

"As always with rainfall, it depends on where the rain falls and the intensity of the falls.

"There's a huge difference between 200 millimetres falling over 48 hours and 200 millimetres falling over two hours."

Meanwhile, the Sunshine Coast council has placed its local disaster management group on alert.

A flood warning has been issued for the Mary River between Moy Pocket and Gympie.