La Paz - Residents of the Tarija province in southern Bolivia favoured more autonomy by a large majority Sunday in a non- binding referendum that Bolivian President Evo Morales considers illegal.

According to an exit survey of voters by Captura Consulting for the PAT television network, 79 per cent of respondents favoured more autonomy while 21 per cent were against it.

A quick vote count made by Ipsos Apoyo for the ATB network said that 80.3 per cent of the vote was in favour of the pro-autonomy proposal. Turnout was 65 per cent.

Tarija, the smallest Bolivian province, holds 85 per cent of the Andean country's reserves of natural gas, which is Bolivia's most important natural resource.

Sunday's vote was the latest episode in a long struggle pitting the left-wing populist Morales - elected in 2005 to become the first president of indigenous descent in Bolivian history - against the wealthier elements of Bolivian society.

Morales is seeking a redistribution of the country's resources to finance his self-declared effort to improve the lot of the country's impoverished indigenous majority.

The Bolivian opposition has turned the pro-autonomy movement in four of the country's nine regions into its preferred tool to attack the Morales government.

Three other provinces have already passed similar referenda - non- binding, according to the country's electoral law - in recent months.

On Sunday, residents of the city of Tarija gathered at the central square Luis de Fuentes despite cold weather to celebrate the reported victory of the autonomy referendum.

"The (central) government did all it could to curb our triumph. It could not do it. Now we have the right to celebrate the unequivocal result," said regional pro-autonomy leader Patricia Galarza.

Santa Cruz held its own referendum on May 4 and favoured more autonomy with 85.6 per cent of the vote. On June 1, two other provinces, Beni and Pando, approved similar referenda by 80 per cent or more. (dpa)