Grim search uncovers further two dead

The last toll from Queensland's flood crisis has risen to 12 and is most sure to keep rising.

The bodies of two men were observed in the Lockyer Valley on Wednesday afternoon, one at a household at Grantham and another in a brook at Lyons Bridge.

There are 51 people missing, a tally revised downwards earlier on Wednesday, and expected to fluctuate as the crisis unfolds, Premier Anna Bligh said.

'It's tragic news that we've had another two deaths . I don't think that's the end of that form of news,' Ms Bligh told reporters.

'To the families of the two men whose bodies were found this afternoon the thoughts of all Queenslanders are with you.'

Deputy Police Commissioner Ian Stewart said recovery teams were searching buildings 'completely ruined' by floodwaters, and combing trees, creeks and cars for bodies.

'Our trust is that we actually might discover some survivors but the chances of that are quite remote,' he said.

Elsewhere in southern Queensland, Chinchilla was brisk for a worse flood than that experienced two weeks ago, with residents now evacuating from homes they had but just moved back into.

Many parts of Ipswich were inundated including Goodna and Gailes and in Brisbane the river was continuing to lift ahead of an expected peak on Thursday.

The riverside suburbs of Jindalee, Moggill and Yeronga were worst hit.

Authorities were considering sinking the Moggill Ferry, which was at hazard of breaking open in the river.

'We don't need it to be a torpedo going down the river,' Ms Bligh said.

Across the state, 3585 people have been strained to get shelter in 57 evacuation centres, including 1500 in Ipswich and 400 in Brisbane.

Ahead of a 5.5 metre peak of the Brisbane River on Thursday, bus services into the CBD have been cancelled, and trains are operating on public holiday timetables.

The Inner City Bypass has been shut and tolls lifted on the Logan and Gateway motorways to give it easier for drivers taking unfamiliar routes due to flooding.

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

Queensland Health's CBD headquarters had been evacuated to the Princess Alexandra Hospital, she said.

'We bear the CBD of our great city to be looking and touch a lot like a ghost town around about now and for ease of the day and the following pair of days,' she said.