The flood clean-up has begun in Gympie in south-east Queensland after the Mary River peaked overnight, inundating more than 30 businesses.

The river is falling slowly and the Bruce Highway remains cut to the south of the city.

Some business owners are cleaning up for the second time in a month and it is the city's fourth major flood in a year.

Gympie Chamber of Commerce spokesman Ben Ellingsen says the cost of successive floods in such a short period of time is devastating for business owners.

"The impact that this has across the whole region is very, very significant," he said.

"When you're trading in a tough economic environment as it is, to have these types of events very close in succession - it's very, very tough for people in business in Gympie."

Gympie Mayor Ron Dyne says floodwaters are slowly receding in the city.

He says Gympie remains split in half by floodwaters and the Bruce Highway is expected to remain closed south of the city until at least this afternoon.

"There's some businesses obviously in Mary Street that have been inundated," he said.

"Those businesses in River Road and One Mile that have been inundated previously at the lower height.

"I'm relieved that it didn't get to 19 metres.

"I would have been even more relieved if it had only got to 10."

Rain easing

Residents should see an easing in the rain that has been lashing the state's east coast with the weather bureau cancelling a severe weather warning.

Moderate to heavy falls are still expected from Bowen south to Gladstone as the focus moves to central Queensland.

But weather bureau senior forecaster Peter Otto says the downpours will not be enough to cause flash flooding.

"The Mary River catchment which is in the Sunshine Coast hinterland area rain has really really eased off through there," he said.

"We still do have a forecast of moderate to heavy falls between Bowen and Gladstone today so there'll still be some decent rain and potential for flooding through there.

"But the flash flooding and the very rapid river rises and stream rises that can really catch people out I think that's unlikely.

"There's only just a few little showers going through there at the moment.

"Again also to the south west - the Lockyer Valley region it's also really cleared up through there as well.

"Pretty much in the south-east it's all about the rain that has already fallen over the last few days."

Sunshine Coast

On the Sunshine Coast, about 80 roads remain closed and locals say flooding has caused major potholes.

An evacuation centre at Nambour is sheltering travellers who cannot go north until the Bruce Highway reopens at Kybong, south of Gympie.

Alan Rogers from the local disaster management group warns more rain is forecast for Friday.

"The outlook is over the next couple of days there will be some showers and the there's possibility of another rain system coming in this time from the west Friday night, Saturday," he said.

"What it says to us is that we need to finish this event, wrap it up, get some rest and be ready and prepared for whatever comes down the line at us in the next few days and weeks."