They said that as the cost of the technology falls and Australia's need for water continues to rise, desalination can now be undertaken economically and on a scale large enough to be a viable option.

Experts say Australia, thought until recently to be emerging from its worst drought on record, now looks like it may not have ended at all -- or it is heading into another one.

While farmers struggle to irrigate crops, residents in the major cities are all now living under strict water usage restrictions as dam levels sink to record lows.

Scientists at Canberra's Commonwealth and Scientific and Industrial Research Organisation (CSIRO) warned Tuesday that the time had come for Australia to seriously consider using plentiful sea water and salty ground water as an alternative source.

The water crisis was illustrated last week with a special conference of state and federal government heads to draw up a plan to try to regenerate one of the nation's biggest river systems, the Murray-Darling which flows from Queensland through New South Wales and Victoria to the South Australian capital of Adelaide.

The river is no longer flowing into the ocean and the river mouth is also taking in salt water.

Australia, along with New Zealand, makes up the world's driest inhabited continent yet is one of the world's highest consumers of water.

Desalination has long been considered too costly but CSIRO scientist Tom Hatton said costs were declining at an average rate of 4.0 percent a year.

"It's getting very close to other new sources of water for a city but the demand is also going up," said Hatton, the deputy director of the CSIRO's land and water division.

Desalination is now used extensively on the Saudi peninsula, while Israel has around 50 desalination plants, and Texas and Florida also use the technology.

"This is a pretty standard approach to water supplies around the world now, particularly in arid areas," he said.

Hatton is based in Perth, Western Australia which is at the forefront of desalination technology in Australia.

Around a dozen such plants have been built by mining companies in remote regions of the state and they are proving very successful, he said.

The West Australian state government is about to decide whether to proceed with a 350 million dollar (242 million US) plant capable of supplying 15 percent of Perth's water.

It would work by reverse osmosis -- forcing sea water through a membrane to trap the salt -- and could be operating within two years.

Technically, the process is even easier with salty, low-quality ground water.

Hatton said the CSIRO is also assessing some towns in Western Australia's wheat growing region which, while frequently drowning in salt water, suffer from severe water shortages and are forced to buy water from Perth.

"Our calculations suggest that we can make water locally from salty ground water that these towns are drowning in at a cost probably much less that the level of current subsidy, so it's win win," Hatton said.

The government last week launched a national water strategy including 500 million dollars funding to restore the flow of the Murray River.

TERRA.WIRE