Election officials count ballots at a polling centre in Santa Cruz, Bolivia on Sunday. (Martin Mejia/AP Photo)

A new Bolivian constitution granting greater power to the country's indigenous majority was approved Sunday by 57 per cent of voters in a referendum, according to an unofficial quick count of votes.

The count, by a private polling firm, showed the proposed charter of President Evo Morales won by 56.8 per cent to 43.2 per cent with more than 90 per cent of precincts reporting.

Yet to be counted were some ballots in pro-Morales rural areas.

The unofficial count results on Sunday were backed by exit polls done by two Bolivian television stations that reported support for the new constitution at 60 per cent or slightly higher.

Early official returns from the referendum also indicated a wide margin of voters favoured the new constitution, which would limit land ownership.

New charter will 'decolonize' Bolivia

Morales, recognized as Bolivia's first aboriginal president, said the charter will "decolonize" Latin America's poorest country by recovering indigenous values lost under centuries of oppression dating back to the Spanish conquest.

Bolivia's Aymara, Quechua, Guarani and dozens of other indigenous groups only won the right to vote in 1952, when a revolution broke up the large haciendas on which they had lived as peons for generations.

"The poorest people are the majority. The people with money are only a tiny few. That's what you have to consider," Eloy Huanca said outside a polling place in El Alto, a sprawling satellite city of La Paz, the country's administrative capital. "They ran things before, and now it's our turn."

Opposition leaders warned the constitution does not reflect Bolivia's growing urban population, which mixes indigenous blood and tradition with a new Western identity, and could leave non-aboriginal Bolivians out of the picture.

"People will go to vote for the possibility of dreaming for a better country, but a country for all of us," said Ruben Costas, opposition governor of the eastern state of Santa Cruz. "We should all be part of this change."

Sunday's vote went peacefully, a relief for a nation where political tensions have recently turned deadly. In 2007, three college students were killed in anti-government riots, and 16 mostly indigenous Morales supporters were slain last September when rioters seized government buildings to block a vote on the proposed constitution. The opposition governor of Pando state, where the riots took place, was accused of complicity in the killings.

New Congress seats for indigenous groups

The proposed new constitution would create a new Congress with seats reserved for Bolivia's smaller indigenous groups and would eliminate any mention of the Roman Catholic Church, instead recognizing and honouring the Andean earth deity, Pachamama.

The document calls for a general election in December in which Morales could run for a second, consecutive five-year term (he was first elected in December 2005). The current constitution permits two terms, but not consecutively.

At the heart of the proposed constitution is a provision granting autonomy for 36 indigenous "nations" and several opposition-controlled eastern states. But both are given a vaguely defined "equal rank" that fails to resolve their rival claims over open land in Bolivia's fertile eastern lowlands, whose large agribusiness interests and valuable gas reserves drive much of the country's economy.

With an eye to redistributing territory in the region, the constitution also limits future land holdings to either 5,000 or 10,000 hectares, depending which voters choose. Current landholders are exempt from the cap — a nod to the east's powerful cattle and soy industries, which fiercely oppose the proposal.

Morales, an Aymara aboriginal, has allied himself closely with Venezuelan President Hugo Chavez in what they call "21st century socialism."

Elected three years ago on a pledge to nationalize Bolivia's natural gas industry, Morales has increased the state's presence throughout the economy and expanded benefits for the poor. He has used his first presidential term to effectively nationalize much of the nation's petroleum and mineral wealth — often to the detriment and against the dissent of foreign corporations and Bolivia's old-guard, wealthy elites.

Sharing Chavez's anti-U.S. sentiment, he has also booted Bolivia's U.S. ambassador and Drug Enforcement Administration agents after claiming they had conspired against his government last year. Washington has denied the allegations.

Morales's reforms remain widely popular, winning him 67 per cent support in an August recall referendum. But his biggest project nearly failed in 2006 when the assembly convened to rewrite the constitution broke apart along largely racial lines.

In an October deal, Congress approved holding the constitutional referendum only after Morales agreed to seek one more term instead of two.