Bolivian President Evo Morales, three weeks away from a recall referendum that could end his historic term as the country's first indigenous leader, nearly met a far graver fate Sunday night when the helicopter in which he normally travels crashed, killing all five people aboard.

The Super Puma helicopter, a Venezuelan air force vehicle that Morales had been flying in just hours before, crashed near the village of Colomi, about 250 kilometres east of the Bolivian capital La Paz, Defence Minister Walker San Miguel said.

It was carrying four Venezuelan soldiers and a Bolivian major from the central city of Cochabamba to the northern community of Cobija, on the border with Brazil. 

Morales was supposed to use the chopper Monday for a flight. It was one of two Super Pumas lent to him in 2006 by Venezuelan President Hugo Chavez, an ally, and meant to replace several Bolivian government helicopters in perilous states of disrepair.

San Miguel said the cause of the crash has not been determined.

Morales, a socialist and Aymara aboriginal politician elected in December 2005, is campaigning across the country in advance of an Aug. 10 referendum that seeks to unseat him from power two years before his term would normally end. Under Bolivian law, more than 53 per cent of voters — a higher percentage than he was elected with — have to opt to recall the president for the referendum to succeed.

Recent polls suggest it will be a close call, with a survey published Monday in Bolivia's El Deber newspaper finding a near 50-50 split on the question of whether to recall the landlocked South American country's leader.

Morales has rankled Bolivia's elite classes with some of his high-profile policies. A former coca grower, he has permitted small farmers to plant subsistence coca crops for use in commercial products like coca-based tea, liquor, cosmetic creams and food. He has also nationalized most of the country's petroleum wealth to bring more of the profits to the poor.