Bystanders filmed as mother swept away in Aust floods

Dozens of men watched, some of them trying to film with their mobile phones, as young Queensland mother Jane Sheahan handed her son Darcy to rescuers and asked them to "save my boy'' before being swept to her death in raging floodwaters.

Details of her last moments came yesterday as thousands of people remained isolated, warnings were issued of more flooding to come, and health threats began to emerge as water receded in devastated areas.

Roma resident Blair Humphries, whose home in the southwestern Queensland town was among thousands inundated over the past week, was one of six locals who tried to reach Ms Sheahan after her car was swept from the road as she delivered sandbags to neighbours last Friday.

Humphries told news.com.au that he and Viv White, Ricky Schefe, Adam Finch, Leigh Hadwin and Angus Anderson had battled to pull mother and son to safety, while dozens of bystanders had merely watched.

Some had even tried to record the tragedy with their phone cameras.

Ms Sheahan and Darcy had been outside the car when he arrived, but were being pulled apart by the water.

Schefe and Anderson tried to reach them with a ski rope, Anderson wedged himself against a power pole further downstream in the hope of grabbing them if they were swept past.

The rescuers managed to reach Darcy - who was a classmate of Humphries' daughter Danika - and passed him to safety. But Ms Sheahan was swept downstream. Her body was found on Sunday.

Yesterday, the worst appeared to have passed in Queensland as a hastily built levee protecting St George continued to hold and hundreds of people evacuated from Charleville on Friday began to return home.

But while officials believe St George may be safe, police late yesterday said the town's 2500 evacuated residents would not be allowed back until the danger was well past.

Waters were receding in Roma and Mitchell, where Queensland Premier Anna Bligh sought military help and more volunteers to help clean inundated homes and businesses.

More than three-quarters of the homes in Mitchell have been seriously damaged.

Resident Alex Tisdell told ABC radio: "People have lost everything, their entire homes.''

Yesterday emergency workers and townspeople formed a human chain across the Maranoa River bridge to pass food, water and other essential supplies into Mitchell.

In NSW about 7000 people yesterday remained isolated by floodwaters, with major warnings issued for the Namoi River at Wee Waa and other, less urgent, warnings for the Narromine, Narrabri and Boggabri areas.

State Emergency Service Commissioner Murray Kear said floodwaters were expected to spread further across the state.

In the worst-hit areas, more than 4000 people could be stranded for between two and eight weeks at Wee Waa, Walgett, Goodooga, Lightning Ridge and Bourke.

Health officials have also warned of rising disease risks because of dead animals, sewage, chemicals and food waste carried by floodwaters.