Amazonian chief Raoni on Thursday implored the UN environment summit here to halt a $13-billion dam being built in one of the world's last bastions of wildlife.

"I want to ask the whole world to respect the indigenous peoples, to leave us in peace... without dams," the 82-year-old chief of the Kayapo tribe, bedecked with bright yellow and black feathers, told AFP.

The chief became known worldwide in the 1980s for teaming up with British rock star Sting for his defense of the rights of indigenous peoples.

He spoke through an interpreter on the sidelines of the Conference on Sustainable Development which opened Wednesday. The giant meeting is to climax in a summit of an expected 116 leaders from June 20-22.

The 11,200-megawatt Belo Monte dam will span the Xingu River, a tributary of the Amazon, in a project billed by Brazil as providing clean energy for a fast-growing economy.

Work began a year ago, despite fierce opposition from local people and green activists.

Indigenous groups fear the dam will harm their way of life while environmentalists have warned of deforestation, greenhouse-gas emissions and irreparable damage to the ecosystem.

The third largest dam in the world, the Belo Monte is expected to flood an area of 500 square kilometers (200 square miles) along the Xingu and displace 16,000 people, according to the government, although some NGOs put the number at 40,000 displaced.

"In this summit, I am going to ask that they respect the rights of those who live near the dam, so that they can continue to fish in the Xingu River, so that my children and grandchildren can fish, eat," said Chief Raoni.

"I am going to ask again here that the Brazilian government stops construction of this dam. I am going to continue defending nature and calling for respect of the forest because my ancestors, my parents lived here first," he said.

Meanwhile, efforts to craft a global deal on the environment for next week's summit made painful progress.

A text to be put to world leaders aims at beefing up governance of green problems and establishing "Sustainable Development Goals" when the UN's current Millennium Development Goals (MDGs) expire in 2015.

Among other things, it would address help for green business and cleaner energy and offer guidelines on how cities of the future can avoid traffic gridlock and slums.

But only a quarter of the 81-page draft communique had been approved as of Thursday, the penultimate day of scheduled negotiations.

Seven "splinter" groups have been set up to try to resolve individual issues.

The mood is "extremely positive" but "many issues are creating more serious problems in finding a solution," Nikhil Seth, director for sustainable development at the UN's department of economic and social affairs, told reporters.

Several concepts have no precedent in UN diplomacy, he explained.

"There is no extant text or registration on which negotiators can moor a language. We are pioneering this work," he said.

Separately, Australia on Thursday announced plans to create the world's largest network of marine parks to protect ocean life, with limits placed on fishing and oil and gas exploration off the coast.

The new reserves would cover 3.1 million square kilometers (1.2 million square miles), or more than one-third of Australian waters, taking in significant breeding and feeding grounds.

It will expand protection of creatures such as the blue whale, green turtle, critically endangered populations of grey nurse sharks, and dugongs.