The Indian authorities are planning to build a 7m tidal power station inside the world's largest tiger sanctuary, the Sundarbans, despite warnings that it could wipe out the tigers' habitat.

Even as the federal government has appointed a special task force to save India's remaining tigers, and amid reports the army is to be sent into wildlife reserves to protect the cats from poachers, the government of West Bengal state is pressing ahead with the proposed tidal power plant.

The Sundarbans is a large area of low-lying mangrove swamps crisscrossed by water channels that lies on either side of the IndiaBangladesh border, southeast of Calcutta. It is believed to be home to as many as 280 tigers, one of the largest wild populations in the world.

Anyone who wants a glimpse of the tigers must venture in by boat, and, unlike elsewhere in India, the tigers in the Sundarbans have a reputation for being man-eaters.

The area's inhospitable geography, verging on the impenetrable, has prevented man from encroaching much, and the Sundarbans has remained largely untouched. As a result it has been a haven for wildlife.

But now the West Bengal government wants to harness its natural tides to make up India's dire power shortages. The plant will allow the tide to rise in one of the Sundarbans creeks, but then trap the water inside and allow it to be released only through a turbine, generating electricity.

"We are going ahead with the project and the environmental hazards will be hardly any because the people behind the project have taken precautions, " the state minister for the Sundarbans, Kanti Ganguly, told Reuters news agency. "This project is important for raising the lifestyle of hundreds of villagers as they cannot live in the dark forever. Once the project starts later this year the perception of the conservationists will change forever."

But conservationists say that the proposed plant will only generate four megawatts of power, enough to light just 15,000 homes, and warn that the potential damage from the plant could far outweigh the benefits. They say the interruption of the natural tides could cause large areas of the Sundarbans to be washed away.

"It is too small a power project but has the potential to wipe out tiger habitat and harm the fragile ecology, " said SR Banerjee, the local director for the World Wildlife Fund (WWF). "We have asked the central government to stop this madness."

The Sundarbans already faces natural sea erosion. Three of the more than 50 islands that lie on the Indian side have been washed away in recent years.

"Once the canal is blocked by sluice gates, the flow of water will be completely restricted, causing widespread sedimentation and siltation, " said Pranabesh Sanyal, a senior official of the national coastal zone management authority. "This will lead to eventual destruction of a large part of the mangrove."

There has been widespread alarm over the future of the tiger in the wild after it emerged last year that India's wild population was far smaller than had previously been thought. Several of the country's leading wildlife reserves were forced to admit that they had far fewer tigers still alive than they had claimed. Some had none left at all. The numbers had been slashed by poachers, and reserve wardens and staff had tried to cover up the disappearances by lying about tiger numbers in their annual reports.