In PHOTOS: Australia's worst flooding in 50 years

Photographs: Daniel Munoz/Reuters

Floodwaters in Queensland are inching towards New South Wales, Australia's most populous state with authorities warning small communities south of the border to prepare for the deluge.

About 400 people in the towns of Goodooga, Weilmoringle and Angledool are facing the possibility of isolation when flood peaks flow into state's north later this month.

While there is no threat to homes but roads are expected to be cut, leaving residents stranded in a handful of communities and surrounding rural properties, according to the State Emergency Service.

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Australia's worst flooding in 50 years

Image: A fish is seen on the Capricorn Highway, which is partially submerged under floodwaters, 6 km south of Rockhampton
Photographs: Daniel Munoz/Reuters

Meanwhile, the weather bureau has predicted moderate to major flooding on the Culgoa, Bokhara, Birrie and Narran Rivers, swamping the region for four to six weeks.

The SES is urging people to prepare now.

"Its weeks away but these are very slow rising floods. Which means roads can be cut a week or more ahead of the flood peak and a week or more after," an SES spokesman said.

Australia's worst flooding in 50 years

Image: A man rides his bicycle on a street affected by flood waters in Bundaberg, Queensland
Photographs: Daniel Munoz/Reuters

"It's not out of the ordinary, these are decent sized floods but they are not exceptionally large like those in Queensland which are floods of record".

Queensland's flood crisis has inundated or isolated more than 20 towns and cities, with more than 200,000 people affected.

Australia's worst flooding in 50 years

Image: Street signs submerged in flood waters are seen in Kendall Street in Bundaberg, Queensland
Photographs: Daniel Munoz/Reuters

The loss of life in the ongoing floods has prompted US Secretary of State Hillary Clinton to express condolences and extending support for providing assistance to its close ally.

Up to 200,000 people are estimated to have been hit by the fast-flowing waters that have inundated 22 rural towns in the country's northeast, across an area the size New South Wales.

Australia's worst flooding in 50 years

Image: Emergency services personnel evacuate people from Rockhampton to Capricorn Highway 6km south of Rockhampton
Photographs: Daniel Munoz/Reuters

The Queensland government estimates the cost to the state could be as high as ASD 1 billion ($980 million). Although the Fitzroy river has not yet at its peak, large parts of Rockhampton were under water and mandatory evacuations were ordered.

Up to 40 per cent of the town could be flooded in next two days, local officials said.

Australia's worst flooding in 50 years

Image: Buildings are submerged in floodwaters in a neighborhood in Rockhampton, Queensland
Photographs: Daniel Munoz/Reuters

According to latest reports, Fitzroy river had swelled to 9 metre overnight and its relentless rise could swamp a record that has stood for more than 90 years.

The airport and road south to Brisbane were closed on Sunday, as were the rail line and road west from the city. The city was cut off on Monday and is expected to remain so for at least 10 days.

Australia's worst flooding in 50 years

Image: Christopher Roth rows down a flooded street in Bundaberg, affected by floods in Queensland
Photographs: Jono Searle/Pool/Reuters

At the airport, flood barriers have been built around the terminal and control tower by emergency teams and cars have been removed from parking in case they float away and cause damage.

"We're looking at alternative means of bringing supplies: barges, heavy-lift helicopters," mayor Brad Carter said, adding, "We might get a bit lean but I can't see this community running out or putting anyone at risk."

Australia's worst flooding in 50 years

Image: Cattle walks through flooded crops near the town of Theodore in Australia's state of Queensland
Photographs: Daniel Munoz/Reuters

A top policeman described the emergency as "unique" because of its huge scale -- the floods cover an area bigger than New South Wales -- which means that as floodwaters recede in some stricken towns and recovery operations begin, others are still bracing for the worst.

Australia's worst flooding in 50 years

Image: Workers of a hardware store start to clean up after being affected by flooded waters in Bundaberg, Queensland
Photographs: Daniel Munoz/Reuters

"I think we are very much in the middle of the event," Queensland Police Assistant Commissioner Brett Pointing said.

"It has got a long way to go."

Australia's worst flooding in 50 years

Image: Owner Brett Jensen looks on as he stands next to his restaurant affected by floods in Bundaberg, Queensland
Photographs: Jono Searle/Pool/Reuters

Meanwhile, a prominent water scientist has forecast widespread damage to the Great Barrier Reef as murky floodwaters surge into the sea off Queensland.

Jon Brodie, a senior research officer with the Australian Centre for Tropical Freshwater Research at James Cook University in Townsville, told a local newspaper The Age that the floods were a "major event" for the reef.

Australia's worst flooding in 50 years

Image: A girl falls in the mud as her sister and father remove damaged belongings from their home affected by floodwater in Bundaberg, Queensland
Photographs: Daniel Munoz/Reuters

"That water will slosh around in the reef for two years," he said.

Fresh water, often containing fertilisers and pesticides as runoff from farmland, kills coral. "It stays there and that is what is actually slowly killing the reef," he said.

Reefs around Great Keppel Island were already suffering from Fitzroy River discharges, he said. "A lot of coral will die."

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