Australian Prime Minister Julia Gillard says the military deployment for the Queensland flood operation will be the biggest for a natural disaster since Cyclone Tracy in 1974.
After talks with the Defence Minister Stephen Smith and military chiefs, Ms Gillard said on Friday that the number of defence personnel working in the state would be boosted to 1200.
Sixteen people are confirmed dead and 53 are missing after flooding in the south-east of the state.
Police say some of the missing may never be found after a torrent of swept through the Lockyer Valley west of Brisbane on Monday, washing away vehicles with people still inside. One body was found 80km from where the person disappeared.
Queensland Premier Anna Bligh says 86 communities have been affected by flooding, with some towns hit three times by floodwaters.
In southern Queensland, optimism is growing amongst residents of Goondiwindi that they may escape serious flooding, although the MacIntyre River is surging through the centre of town on Friday night.
Water surrounds the town of 6000 people, which lies on the border with New South Wales, and the river has reached a record high.
It is expected to peak at 10.85 metres, just below the height of the 11-metre levy bank which is holding the river back so far.
Brisbane starts cleaning up
A massive flood clean-up operation is gathering pace in Brisbane as flood waters recede. In the city's western suburbs, the army has dropped food into areas still cut off due to flooded roads.
The Brisbane River has fallen to just above three metres and is continuing to subside. It peaked at 4.46 metres on Friday morning.
However, large parts of the city of Brisbane remain submerged. More than 20,000 homes and businesses are inundated and 118,000 buildings are without power.
Many homes in the riverside suburbs of Chelmer, Graceville and Indooroopilly are still submerged, with water lapping at the awnings. Worst-hit areas include the central business district and the suburbs of St Lucia, West End, Rocklea and Graceville.
SEQ Water says the storage levels of Wivenhoe and Somerset dams are gradually falling. The ABC reports about 1 million megalitres of water a day were flowing into the dams during the peak of flooding.
Water levels fell significantly overnight on Thursday in Ipswich, where 3000 homes and many businesses have been flooded. After peaking overnight at 19.5 metres, the river is now below 14 metres and dropping rapidly on Friday.
Extra police are being brought in to patrol flooded areas in Brisbane and Ipswich to provide security and prevent looting.
60 schools damaged
Queensland Premier Anna Bligh has confirmed 60 schools in the state are significantly damaged but every effort will be made to ensure there is as little disruption to education as possible.
Eighty-six kindergartens and childcare centres are also inaccessible. The ABC reports seven TAFEs have also been damaged.
Ms Bligh says the state government is determined that as many schools as possible will open when the new term starts later in January.