Evo Morales, the Bolivian president, has begun a hunger strike aimed at pressuring the country's parliament to set a firm date for general elections that he is likely to win.

Morales, who took office in 2006, has said opposition politicians are trying to block the poll, which was approved by voters as part of a constitutional referendum held in January.

"Faced with the negligence of a bunch of neo-liberal lawmakers, we have no choice but to take this step [hunger strike] ... they don't want to pass a law that guarantees the implementation of the constitution," Morales said at the presidential palace in La Paz on Thursday.

Fourteen leaders of labour and social groups said they were joining the president on the hunger strike.

'Unreliable census'

The constitution calls for the Bolivian congress to approve an electoral law ratifying December 6 as the date for a general election.

But the opposition has rejected the bill because it gives 14 seats to minority indigenous groups which, they say, amounts to giving them to Morales, who has the support of indigenous groups.

They also want a new electoral register ahead of the election, saying the current census is not reliable.

The election bill has also been held up by arguments over whether Bolivians living outside the country should be able to vote.