Mr Newman said that based on the 1974 flood experience, it will take at least three or four days for the floodwaters to go down.
"This morning our team will be working through the initial plan for the clean-up," he told the Nine Network.
"I'm calling on Brisbane residents who haven't been affected to put the shoulder to the wheel and get involved in one of the biggest community clean-ups since 1974.
"This is a big community working bee and I'm going to be asking every able-bodied man and woman and even able-bodied kids to be part of this."
At Ipswich, where the Bremer River flooded 3000 homes and inundated businesses in the CBD, levels had fallen below 18 metres on Thursday morning, from the 19.5 metre peak, with efforts now turned to the clean up.
Evacuations
Queensland Premier Anna Bligh said authorities remained on high alert despite the Brisbane River peaking lower than anticipated.
"There is still a very dangerous situation and we have thousands of people who are waking this morning to the total devastation of either their home, their businesses," she told ABC Radio.
"This is still a very anxious time."
Blue sky, no rain, and slightly lower river levels was some "good news after a lot of time without it".
The premier has also warned that some Brisbane residents may not be able to move back into their flood-affected homes for months.
Brisbane City Council said the areas most affected by flooding in the city were the CBD, St Lucia, West End, Rocklea and Graceville.
Some 15,268 residential and commercial properties were affected today, it said. The council said flooding had also closed more than 150 roads.
Brisbane Lord Mayor Campbell Newman said about 11,900 homes have been fully flooded, with another 14,700 partially affected; 2500 businesses have been flooded with the same number partially affected.
Residents whose properties are expected to be affected by flooding should have self-evacuated either to the homes of family or friends, or to one of four evacuation centres in the city, police said.
Brisbane City Council said 700 people were now staying now staying at the evacuation centre at the RNA Showgrounds, Bowen Hills, while 325 people have self evacuated to the centre at QEII, Nathan.
Police are advising people to stay out of the floodwaters as they contain debris and contaminants.
Sightseeing is also being discouraged and residents have been told to limit all non-essential travel.
More than 115,000 Queensland homes were this morning without power. Power company Energex said around 78,000 of those properties were in Brisbane and another 30,000 in nearby Ipswich.
Recovering the dead
Police working to recover bodies in the worst-hit area of flood-ravaged Queensland yesterday described scenes of heartbreak and devastation.
One officer in the Lockyer Valley, about 100km west of Brisbane, said the task of recovering the dead was "simply horrific".
"We are searching for in excess of 30 people and at this stage we are in a body-recovery phase," a police spokesman said.
"We are recovering numerous bodies from the river and are prepared to recover many more."
All of the confirmed deaths in this week's floods were in the Lockyer Valley and the nearby cities of Toowoomba and Ipswich.
The official death toll stands at 12 with police not yet officially adding the death of a man whose body was found in a submerged car in Ispwich overnight.
Five of the deaths were in or near the small town of Grantham, which has a population of about 370.
The toll is likely to rise further, with authorities holding grave fears for 12 people, most of them from two families, who are still missing in the devastated valley community of Murphys Creek. A further 74 are reported missing.
- staff reporter, AAP, Toowoomba Chronicle, NZ HERALD STAFF, NEWSTALK ZB
Watch live video of the Brisbane River in flood:
