[GALLERY id=4271 cat=world]

The Australian town of St George was being evacuated Tuesday before flood waters inundate the area.

Australia's Queensland state remains in the grip of a flood crisis, with cities and towns such as Emerald mopping up and others, including Rockhampton, waiting for rivers to peak.

St George residents were put on heightened alert after the weather bureau revised its flood threat for the town.

Authorities in St George spent a frantic day building levees to protect the town, but the shire mayor believes the council's hard work will save all but about 30 homes.

The hospital has already started removing patients, beginning with seven seriously ill patients who were flown out of St George.

The remaining hospital patients are to be discharged before flood waters peak early next week.

Emergency services established a temporary medical centre.

The local nursing home is to be evacuated Wednesday morning, with residents to be flown to Brisbane.

Queensland Ambulance Service spokesman Jeff Shelberg says special 25-bed shelters can provide high-level treatment.

"We're able to provide a critical care unit as part of that — that's full resuscitation as well as a level of observation and care," he said.

tp-rockhampton-flood-cp-rtx

Emergency personnel unload their boat in flood waters in Rockhampton, Australia, on Tuesday. ((Daniel Munoz/Reuters))

"At that stage of being occupied we'd be asking Queensland Health to assist in that regard as well."

Local people know what to expect from the floods — St George was hit by a huge flood in March last year.

The bureau now expects the Balonne River to peak at 14 metres late on Sunday or Monday. But hydrologist Peter Baddiley says the river could go even higher.

"It'll be reaching the level of the March 2010 flood around Friday night," he said.

"Fourteen metres on Sunday and a peak possibly higher than 14 metres on Monday [or] Tuesday."

The town of 3,500 is already isolated and the predicted peak would inundate 80 per cent of the town.

St George businessman Graham Nosse says around six people have built makeshift moats in a bid to protect their homes from floodwaters.

"They've been carting in lots and lots of truckloads of dirt and then put out by a tractor to lay it out," he said.

"I'm sure not exactly how high they'd be, probably one-and-a-half, two metres high. They're all around the houses, they've gone front to back and sides. So it's like a house within a castle wall."

Adding to the flood threat, a big rain front is headed towards the region.

Emergency Management Queensland says emergency services workers will head to St George once the flooding in the central Queensland city of Rockhampton subsides.

Meanwhile, people in Rockhampton were being warned to stay out of the water, and not just because of the risk of being swept away: Debris, snakes and even crocodiles could also pose a danger.

With files from The Associated Press