Most Bolivians who voted in Sunday's election to choose the country's top judges cast invalid ballots in what would be a stinging rebuke for President Evo Morales’ plan for judicial reforms, according to unofficial partial results.

A count by Ipsos Apoyo, an opinion polling firm, said void votes accounted for between 46 to 48 per cent of ballots, private television channel ATB said on Monday.

It said valid votes accounted for about 38 per cent and the remaining ballots were blank, with 76.2 per cent of the count completed. Absenteeism was estimated at around 20 per cent.

Bolivia's 5.2 million registered voters were asked to choose members of the country's four national courts from a list of 116 candidates. Half the candidates were women and many are indigenous.

The government said the judicial ballot will help in holding judges more accountable and improve the judicial system.

Electoral authorities had expected the first official results to be released on Sunday, but as of midnight (0400 GMT), they had not been made available.

The opposition had urged voters to abstain from voting or cast blank ballots in the first election to directly select the country's top judges.

They contended that the election would erode the independence of the judiciary and strengthen Morales because the 114 candidates were chosen by a Congress dominated by his governing MAS movement.

Until now, these judges were chosen directly by Congress.

If the results hold, it would be the first defeat at the polls for the Andean country's first president of indigenous descent of his nearly six-year presidency.

'Refounding of Bolivia'

Morales, looking disheartened, declined to discuss the outcome of the election, but said turnout had been high. Voting is compulsory in Bolivia.

"Some said there wouldn't be participation of the people in these elections," Morales told reporters in La Paz on Sunday night. "Those who tried to boycott these elections failed."

The leftist leader had billed the election as "the next step in the refounding of Bolivia".

The judicial shake-up was the latest in a series of reforms that Morales says will help reverse five centuries of discrimination against indigenous peoples and domination by a European-descended elite.

While the candidates with the highest number of votes would win, regardless of how many invalid votes were cast, analysts said such an outcome is likely to intensify social malaise.

The opposition has also accused Morales of using the judiciary to persecute adversaries.

A leading opposition politician, Samuel Doria Medina, said the results proved the election was "illegitimate". He called for starting the judicial selection process from scratch.

Morales comfortably won re-election in December 2009 but his popularity has plummeted in the past year over policy decisions that angered many Bolivians.

Discontent has already brewed after police broke up a march against the construction of an Amazon highway, triggering political fallout that led to the resignation of the country's interior minister last month.

He also had to reverse his decision to end subsidies on gasoline after major protests in Bolivia which is the region's biggest natural gas exporter.

Morales has indicated he wants to run for a third term in 2014.

Source: Agencies