President Evo Morales on Tuesday offered direct talks with almost 2,000 indigenous people about to end a grueling protest march against government plans to build a highway through an Amazon nature preserve.

Morales, the first democratically elected indigenous president of this South American nation, finds his leadership challenged by a thorny national political debate over juggling native peoples' rights and economic development.

"This dialogue would aim to iron out and build consensus on their demands in the framework of broader political action," Morales' spokesman Carlos Romero said in a statement carried by the official news agency ABI. The talks could be held as soon as late Tuesday or Wednesday, Romero said.

Planners want the Brazil-financed road to run through the Isiboro Secure National Park and Indigenous Territory, leveling an ancestral homeland inhabited by 50,000 native people from three different native groups.

Work on the highway, which had been due to be operational in 2014, began in June, although not on the segment running through the protected park.

These isolated peoples from the humid lowlands are not from the main indigenous groups that make up most of majority-indigenous Bolivia's population, the highland Andean Aymara and Quechua.

The lowland people fear their traditional lands may be overrun by landless highland farmers.

Earlier the marchers, weary after weeks of walking but energized ahead of an expected triumphant entry into La Paz, massed in Pongo. It was not immediately clear what their response to Morales offer would be.

"We have no confidence in the Bolivian government. All they do is lie," said Fernando Vargas, leader of the demonstrators, gasping for breath as the group approached the highest-altitude capital city in the world.

The marchers, including women, children and elderly people, left the northern city of Trinidad in mid-August and have endured heavy rains, low temperatures, difficult mountainous terrain and police brutality during their 600 kilometer (370-mile) journey.

Earlier this month, Morales agreed to postpone construction of the roadway, a delay that was later approved by Bolivia's legislature. But the protesters are seeking assurances that the project -- or at least the Amazon portion of it -- will be scuttled for good.

"If work begins, we will fight in the forest until death," said indigenous leader Adolfo Chavez.