The death toll from the Australian Queensland floods disaster has risen to 12 and more than 3500 people have been forced to take shelter in 57 evacuation centers across the state as floodwaters continue to rise, said Queensland Premier Anna Bligh on Wednesday.

Announcing the increase from the previous figure of 10 confirmed deaths, Bligh said thousands more had fled their homes and sheltered with family and friends on higher ground.

Of those in evacuation centers some 1500 are in Ipswich and 400 are in Brisbane.

"We expect that number to grow as their rivers start to swell and peak this afternoon and overnight," Bligh told reporters in Brisbane on Wednesday afternoon.

Bligh said bus services into the Brisbane Central Business District (CBD) had been canceled but trains were operating on public holiday timetables.

The Inner City Bypass has been closed and tolls lifted on the Logan and Gateway motorways.

Bligh said public hospitals had generator back-up power and were located in areas safe from flooding.

"Anybody who has any critical health issue can rest assured their hospitals are operating," she said.

All non-urgent surgery has been canceled, but emergency and high-need patients will be seen.

Queensland Health officials involved in emergency disaster management and public health have been moved from their Brisbane CBD headquarters to the Princess Alexandra Hospital, a 10-minute drive South of Brisbane CBD.

"We expect the CBD of our capital city to be looking and feeling a lot like a ghost town around about now and for rest of the day and the next couple of days," Bligh said.

Bligh said the Bremer River in Ipswich was still expected to peak on Wednesday afternoon at 20.5 meters.

State disaster coordinator Ian Stewart said recovery teams were searching buildings "that have been completely destroyed" and combing trees, creeks and cars for bodies.

"Our hope is that we actually might find some survivors, but the chances of that are quite remote," Stewart said.