Eight people were killed with over 70 others missing, as flash floods swept across southeastern Queensland State of Australia, local police said on Tuesday.

A street is covered by a flash flood in Toowoomba, Queensland January 10, 2011. Residents in Australia's third largest city, Brisbane, sandbagged their homes against rising waters on Monday, as police warned people in smaller outlying towns to be ready to abandon homes as forecasters predicted more heavy rain. [Xinhua/Reuters]

Queensland police deputy commissioner Ian Stewart said 72 people were missing in the areas like Lockyer Valley, west of Brisbane, which was trapped by the massive flooding. Dozens are stranded, waiting for help.

"Mother nature has delivered something terrible in the last 48 hours but there's more to go," she told the Nine Network, noting that more tragic stories may take place Tuesday. Rescue crews fear that the toll may rise, with so many missing.

The defense force is participating in a vast search and rescue mission playing out in Lockyer Valley after it was hit by walls of water that earlier tore through Toowoomba.

Police urged up to 5,000 people to flee their homes Monday night, warning of a "7m wall of water" as the flood surged into the Lockyer Valley, east of Toowoomba. Earlier, police said the dead included a woman and a boy, whose bodies were found in the Toowoomba CBD. A man and a boy were also dead after being washed away in, or from a house, at the valley community of Murphys Creek.

The destruction in Toowoomba marked a escalation of the flood crisis that has affected much of Queensland since the end of last year. Economists said the flood can bring about billions of dollars of damage to Australian economy.

In northern New South Wales, there are more than 700 residents remained isolated by flood, who were also on alert Monday night. The Bureau of Meteorology on Monday issued a severe weather warning, with rain forecast to intensify overnight and possible flash flooding in the mid-north coast, northern tablelands and northern rivers regions.