Brazil took a step forward in protecting the Amazon rainforest yesterday, starting satellite surveillance of the cattle ranches that are among the chief culprits in the forest's destruction.

The agriculture ministry will monitor more than 15,000 cattle ranches, many of which were established by clearing forested land, and stop ranchers from selling their cattle if they expand farms further by encroaching upon the rainforest.

"We can now say that Brazil is doing its part," said Agriculture Minister Reinhold Stephanes at the launch of the plan in Para, one of several states in the north of Brazil over which the world's largest rainforest sprawls.

Brazil's efforts to protect the Amazon are under the global spotlight this month as heads of state meet at the climate change conference which began this week in Copenhagen.

Cattle ranching is one of the main causes of deforestation, which accounts for about 75 per cent of Brazil's carbon emissions. The scheme is one of the few measures taken to date by the farming ministry to control ranchers, showing heightened awareness of the link between success in exporting and the foreign consumers' desire for more ecologically sound produce.

A major report in June by environment group Greenpeace on the Brazilian cattle industry's deforestation spurred a rash of pledges by big meat firms to cut ties with suppliers producing on illegally cleared land.

Ranchers who have been identified via the satellite images as illegally claiming forested land to expand their pastures will be unable to obtain a permit enabling them to transport their cattle to slaughterhouses.

Up to now, the government's environment agency, Ibama, has led the battle, confiscating the cattle of ranchers found slashing and burning their way into the forested land, occasionally leading to violent confrontations.