Morales, who has vowed to roll back a U.S-backed campaign to eradicate coca leaf growing, had between 47 percent and 50 percent support, according to results tabulated by four local television stations.

The results showed Morales with a much wider lead than had been predicted in pre-election polls, meaning he could easily pass a hurdle in Congress, which must decide between the two top contenders if none gets more than 50 percent of the vote.

Jorge "Tuto" Quiroga, a conservative former president, was in second place with between 31 percent and 33 percent of the vote, according to the media tabulations.