The government's plans run counter to advice from experts at the World Commission on Dams (WCD), an independent body of international experts, who say dams should be avoided in areas rich in species -- like the Amazon which is home to an estimated 30 percent of the world's animal and plant species.

"The Amazon, Congo, Nile, Parana and Yangtze watersheds are the most species-rich, with the Amazon far ahead," WCD specialists said in a report.

Brazil's plans include two dams on the Madeira, a main tributary to the Amazon, at a cost of $9 billion to produce 6,400 MW of electricity. The project, in Rondonia, will flood 550 sq km (210 sq mile) of forest.

International Rivers Network said the dams would threaten the survival of several species of large catfish that migrate some 4,500 km (2,800 miles) to breed in the upper Madeira.

Thirty-three endangered mammal species live in the region to be flooded, including the spotted jaguar, the giant anteater, the giant armadillo, giant otter and several species of birds.

The government says the Madeira project is critical if the country is to keep pace with energy demand in the next decade.

The case illustrates the dilemma facing many developing countries -- often rich troves of biodiversity but also struggling to cater for poor, growing populations for whom environmental concerns often seem an unaffordable luxury.

It's a conflict-of-interests that will likely hang over United Nations talks on biodiversity, opening in Curitiba, Brazil next week.

"NECESSARY? NO"

Brazil's government wants to protect the country from the kind of power crisis caused by a 2001 drought. Then, hydroelectric power accounted for around 95 percent of total generation capacity and rationing crippled growth.

Environmentalists say the government has overestimated future demand for energy and even energy sector leaders have doubts about the Madeira plan, and a second project on the Xingu river, called the Belo Monte.

"Necessary? No," Claudio Sales, head of the Chamber of Electric Energy Investors, said. "These mega-projects are not indispensable, although the government is trying to present them as such. This is a big mistake."

Sales said several smaller hydroelectric projects could easily meet energy needs, already had environmental clearance and could actually deliver cheaper energy to the consumer.

The massive 11,000 MW Belo Monte Hydroelectric Complex would flood the Xingu river basin and cost close to $7 billion.

Belo Monte was first proposed years ago and shelved because of public anger over the environmental and economic costs. The government is trying to get a revised version approved for 2007.

Although the Belo Monte dam is seen as efficient in terms of energy per dollar invested and area flooded, the rate of flow of the Xingu drops drastically from June through August and would seriously reduce its generation capacity.

"The obvious conclusion is that other dams upstream are being planned, and the energy sector does not deny this, so that large volumes of water can be stored to turn the turbines at Belo Monte during the dry season," Glenn Switkes, the South American specialist for International Rivers Network, said.

There is a plan to build a massive reservoir called Altamira, about four years after Belo Monte is completed. This would flood 6,100 square km (2,355 sq mile) of dense forest, a good portion of which is part of the Xingu Indian reservation.