The lake, in the south-west corner of the island, one of the world's most remote regions, used to be considered a natural wonder for its white quartzite beaches and the way its still waters reflected the sky and surrounding hills. In 1972, ignoring a public outcry, the Tasmanian government sealed the Serpentine River, which flowed out of the 3.5 sq mile lake, obliterating it under a 75 sq mile dam to serve the electricity grid.
The restoration project has been launched by a group of environmentalists in Australia, who believe that there is now enough public support to force the state to reverse the drowning of the lake. They want the plug pulled on the dam by 2000. Rather than smashing down its walls - which could remain as a monument to engineering folly - they want its floodgates opened to reveal the lake in its pristine beauty.
Bob Brown, a Green Independent MP in the Tasmanian parliament and a leader of the campaign, said: 'Lake Pedder's restoration will bring hope to a new generation in the last hour of a destructive millennium.'
The original campaign to save Lake Pedder marked the launch of the environmental movement in Australia in the 1970s. That unsuccessful battle pitted ordinary citizens against a government which was prepared to sacrifice a unique wilderness area in the name of economic development. Prince Philip, then president of the Australian Conservation Foundation, said at the time he hoped 'that never again will Australians have cause to question so vehemently a decision on any conservation issue'.
For many, the lake has never been forgotten. In 1982, its memory triggered a vociferous campaign to stop the Tasmanian government from building yet another dam and flooding the Franklin River and its ancient caves containing aboriginal paintings dating back to the ice age. The state lost that
battle, which ended with about one-fifth of the island being declared a World Heritage area.
Mr Brown, a former doctor who, with Mr Bellamy, was arrested while demonstrating to save the Franklin 12 years ago, believes that day has now come. They received a boost when the International Union for the Conservation of Nature, meeting in Buenos Aires in January, called on the Australian government to support the restoration as a symbol for recovering some of the world's heritage.
The six-year campaign was launched last month with a study, by Professor Peter Tyler of Deakin University in Victoria, which says that the lake's main features remain largely intact. On the basis of echo soundings, Mr Tyler said the sand dunes and beaches would most likely regain their former appearance within a few months.
Mr Brown argues that the the spin-off from tourists would outweigh the dam's minimal contribution to an island that already has more electricity than it needs. Three weeks ago, Prince Philip wrote to the campaign organisers saying that the chance to restore Lake Pedder was 'a great good fortune'.
But is it just a pipe dream? Robin Gray, Tasmania's Minister for Energy, says there will be 'fairly strong resistance'. But he is subdued compared with his campaign against the 'Greenies' over the Franklin River dam 12 years ago - a battle he resoundingly lost.
Mr Brown shows no such reticence. 'This will be part of an international celebration in 2000 for ecological restoration next century,' he says.