Gympie is in the grip of more flooding in the wake of the torrential rain that has buffeted south-east Queensland.

While the rain blanketing the south-east of the state is nowhere near as heavy as that recorded during the Australia Day long weekend, authorities are still warning that flash flooding is possible from Bundaberg south to Brisbane.

Gympie's central business district has flooded again for the fourth time in a year, with the Mary River expected to peak at up to 19 metres.

Shops started going under at 15m, and the river level passed 17m on Wednesday afternoon.

It is believe that about 40 businesses will flood, in devastating news for a city still recovering from the Australia Day flood when the river peaked at more than 20m.

Tim Steele from Emergency Management Queensland says the river is rising slowly.

"It's rising at about 300 millimetres an hour, so it's a long flood peak, and possibly a slow drop tomorrow," he said.

The Bruce Highway remains closed south of Gympie and is not expected to re-open until Wednesday afternoon.

Emergency services are still urging motorists to avoid non-essential travel and not to cross flooded roads.

Gympie Mayor Ron Dyne says homes should not be affected when the Mary River peaks.

"Those businesses that are impacted at that height have vacated their premises," he said.

"It certainly is unfair. They're suffering emotionally, financially and all other ways.

"It's a fair slap in the guts for most people.

"People are just shattered and there's very little you can say for them other than to prepare and hope like hell."

Panel beater Tony Alford has spent the night and all day clearing out his panel beating shop.

He says his business loses several weeks of trade every time a flood comes through.

"Two weeks since we started - probably take two weeks to catch up again, so [we're] sort of chasing our tail at the moment," he said.

Flooding has forced the cancellation of several clinics at the Gympie Hospital for the next two days.

All patients due for chemotherapy, surgery and specialist outpatient services will be contacted later this week to have their appointments rescheduled.

Future planning

Gympie Deputy Mayor Tony Perrett says it is time to start considering a plan to reduce the impact of flooding on the city.

Council is considering a study to find ways to alleviate the risk of inundation on businesses in the flood prone CBD.

Councillor Perrett says it may include relocating some shops to higher ground.

"That's a discussion that we're prepared to have with the State Government," he said.

"Obviously they have a few issues that they need to deal with right across Queensland you know in flood-prone areas.

"Gympie is one of those ones that keeps coming up time and time again and if that's something that is viable and something that those businesses wish to do then that's something we can discuss with a higher level."

Bundaberg on alert

Many regions of south-east Queensland are on flood alert as heavy rain continues to fall. ( ABC: Bruce Atkinson )

In the Bundaberg region, up to 200 millimetres of rain is expected to fall in some isolated areas over the next 24 hours.

Mayor Mal Forman says there is no immediate flood threat for the Burnett catchment.

But he says it is important that residents take precautions.

"Anyone who may be in a low-lying area to take those precautions now and do any things they need to do to - pack things up or start to look at possible moving," he said.

"At this point in time it's still at only the minor thing and we should not get the flooding here at this stage."

Man dies

Flooding on Rifle Street in Pomona, in the Sunshine Coast hinterland. ( ABC News: Bruce Atkinson )

On the Sunshine Coast, heavy rain has now eased.

A man drowned yesterday afternoon trying to cross a flooded road at Kilcoy, north of Brisbane.

The body of the 77-year-old Sunshine Coast resident was found by police after his car sank in floodwaters.

He was the seventh person to die this year as a result of extreme weather events in Queensland.

Further north, a woman reported missing in bushland at Pomona, in the Sunshine Coast hinterland, has been found safe and well.

The woman abandoned her vehicle in floodwaters yesterday before becoming disorientated and walking into bushland.

A family of three, meanwhile, escaped unharmed yesterday after their car was inundated near Nanango.

Last night, crews rescued a motorist from floodwaters in Marsden, south of Brisbane.

Another couple were rescued from a flooded car in Nanango this morning, while crews used a boat to retrieve a motorist who was stranded on dry land at Kadanga in the Sunshine Coast hinterland.

Lockyer alert cancelled

Debris resulting from days of storms and bad weather covers Main Beach on Queensland's Gold Coast on February 25, 2013. ( Audience submitted: Vivien Willicombe )

Meanwhile, a flood alert for low-lying areas of the Lockyer Valley has been cancelled, with residents no longer being urged to evacuate.

Evacuation centres were set up last night at Laidley State High School and Alexandra Hall in Toogoolawah.

The local council says flood levels are easing along Laidley Creek at Mulgowie, but are yet to peak in some areas such as Glenore Grove.

Hydrologist Jess Carey says Laidley Creek peaked at 8.79m overnight.

He said it was almost half a metre lower than the Australia Day flood which inundated parts of the town.

"There may have been some local effects in the town of Laidley, another significant flood through Laidley. Also minor to moderate flooding moving through the Bremer and Warrell systems," he said.

"We are forecasting peak at 7m at Walloon and a peak level, minor flood level at Ipswich Tuesday afternoon."

Disaster management coordinator David Mazzaferri says nine people spent the night in a local evacuation centre in Laidley.

"We had some low-lying areas inundated but we were pretty fortunate that it didn't reach the heights of January," he said.

"Water over roads, isolated but at this stage no inundation of houses. Plenty into yards, but no dwellings."

Seqwater said it needed to increase releases from Wivenhoe Dam and Burton's Bridge was expected to be inundated by noon (AEST).

In Brisbane, more than 100mm has fallen since yesterday morning, with the SES receiving 230 calls for help with sand-bagging and covering leaking roofs.

Dam releases

SEQ Water says it is now releasing water from the four major dams in the south-east.

The volume is being reduced at Wivenhoe, Somerset, North Pine and Leslie Harrison dams.

Some local roads and crossings have been closed as a result.