"The dam is having a titanic social and environment impact," the group said in a press release in Paris.

FoE said the dam, which it costed at 25 billion dollars, was 50-percent more expensive than originally estimated and the project was stained by corruption.

After it becomes operational, the 660-kilometre (412-mile) reservoir created by the dam will drown 13 towns, 4,500 villages and 162 archaeological sites, FoE said.

"Sometimes people are being moved out by truncheon and bulldozer because they refuse to leave their home for fear of not being rehoused. Human rights violations are massive and brutal," it said.

FoE pointed to evidence that the dam was already having a serious environment impact.

It referred to a study by scientists at the East China Normal University in Shanghai, published in March in the US journal Geophysical Research letters, which said that in 2004, the Three Gorges dam had reduced the supply of sediment to the Yangtze delta to just 35 percent of the norm.

As a result, the tidal wetlands around Shanghai are eroding swiftly, damaging the coast's fragile ecological systems and curbing the city's ability to expand, the scientists warned.

Supporters of the Three Gorges say the scheme will control chronic and sometimes deadly flooding of the Yangtze. They also argue it will help meet China's energy needs with a renewable source that will not add to greenhouse gases that drive global warming.

Critics say the claim about flood control is unproven and contend that silting may eventually jam the dam's turbines.

They also say that the final cost of the scheme, if relocation and other costs are factored in, will make its electricity prohibitively expensive compared with smaller renewable alternatives.

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