The blaze has already ravaged more than 3,200 square kilometres of pastures and forests and destroyed 500 cows in the central state of Mato Grosso.

Fires fuelled by worst drought in 30 years

It is now within 4km of Xingu National Park, home to more than 5,000 members of 17 indigenous Indian groups.

Brazil's Environment Institute has put a new rapid response plan into action for the first time, sending 30 firemen on an air force plane to the burning area.

The plan was drawn up earlier this year after huge fires raged out of control through savanna and rain forest on the northern border.

During the dry season, slash and burn practices in rural areas are responsible for tens of thousands of fires throughout the country.

But this year has seen a 69% increase in fires during the traditional slash and burn months from June to August, according to the Brazilian newspaper `Jornal da Tarde'.

Emergency talks

The armed forces and Indian tribes have been called on to help tackle the Mato Grosso blaze.

But environment officials say the lack of infrastructure in the region is hampering their work. The nearest town has only one police car and no firefighting equipment.

Regional authorities have declared a state of emergency and conscripted all vehicles to help firefighting efforts.

Brazil's Environment Minister, Gustavo Krause, is meeting government officials to discuss the disaster.

Yanomami Indians tackle fire in March

But with the fire advancing at a speed of 4km an hour there is little time to act before the 2,000,000 hectare Indian reserve is seriously threatened.

A spokesman for the government's National Indian Foundation said: "It's no distance at all. The fire could be in the park very quickly.

''The situation is very serious. We have declared red alert."

Xingu National Park is considered the showpiece of Brazil's efforts to protect the country's Indian peoples from the modern world.

Few speak Portuguese, and ancient ceremonies, like the festival to commemorate the dead, are strictly observed.