But conservationists fear large areas of the swampy mangrove park, home to about 280 tigers in the eastern state of West Bengal, will be washed away in the process.

"It is too small a power project but has the potential to wipe out tiger habitat and harm the fragile ecology," S.R. Banerjee, state WWF director told Reuters.

"We have asked the central government to stop this madness."

Three of the 50 or so islands that make up the Indian side of the Sunderbans -- the rest lie in neighbouring Bangladesh -- have been lost to sea erosion in recent years.

S.P. Gon Chowdhury, director of the West Bengal Renewable Energy Development Agency and architect of the scheme, said there was no cause for concern.

"We will get all necessary clearances before starting the work later this year," he told Reuters. "There will be no threat to the tigers."

The state minister for the Sunderbans, Kanti Ganguly, said the environment would be protected and the project was important for improving the livings standards of hundreds of people.

"We are going ahead with the project and the environmental hazards will be hardly any because the people behind the project have taken precautions," he told Reuters on Friday.

"This project is important for raising the lifestyle of hundreds of villagers as they cannot live in the dark forever.

"Once the project strarts later this year the perception of the conservationists will change forever."

But environmentalists say it is hard to see how the plant -- which would be India's first tidal power scheme -- can avoid both eroding some areas of the 350 sq km (135 sq mile) park and silting up others as the natural flow of water is disrupted.

"Once the canal is blocked by sluice gates, the flow of water will be completely restricted causing widespread sedimentation and siltation," Pranabesh Sanyal, a senior official of the National Coastal Zone Management Authority, said.

"This will lead to eventual destruction of a large part of the mangrove," he said of the region where the river Ganges flows into the Bay of Bengal.

The state government plans to construct two sluice gates at either end of the Durgaduani creek, which connects two rivers.

During high tides, sea water will be allowed into the creek and as the level rises it will be released through a turbine.

Over the past year, Indian officials, including Prime Minister Manmohan Singh, have expressed alarm at reports of a dramatic fall in the tiger population because of rampant poaching and human encroachment on leading sanctuaries.

A century ago, there were about 40,000 tigers in India but according to official estimates, there are now barely 3,600 and some wildlife experts say there could be fewer than 2,000.