CARACAS Venezuela's President Hugo Chavez has a 16-percentage-point lead over opposition candidate Henrique Capriles ahead of an election in October, a new opinion poll showed on Tuesday.
The survey by respected local pollster Datanalisis found that 43.6 percent of voters favor Chavez, versus 27.7 percent for the Democratic Unity coalition's candidate Capriles, according to one person who viewed the privately commissioned poll.
It said the portion of undecided voters had declined slightly in May but still stood at a substantial 28.7 percent - meaning there is a lot left to play for. Datanalisis did not immediately respond to a request for comment on the figures.
Chavez, 57, who has been battling cancer for a year, remains popular in his 14th year in power due to his oil-financed welfare spending and his enduring emotional connection with the poor majority in the South American OPEC nation.
State governor Capriles, 39, however, is drawing big crowds on the campaign trail and exuding an image of youth and energy that he believes will tip the balance come voting day on October 7.
The new Datanalisis survey was in line with most of the country's best-known pollsters, who give Chavez a double-digit lead with less than four months left until the ballot.
Opinion polls are notoriously controversial in Venezuela, with both sides regularly accusing the companies that publish them of being biased and having political links.
While Chavez appears to be in a strong position, analysts say the volatility of Venezuelan voters and the mystery over his health mean the 2012 presidential race is far from over.
After three operations to remove two cancerous tumors in the last year, and lengthy absences in Cuba for treatment, Chavez has returned to the public limelight in the last two weeks with regular appearances on state TV and in public.
Details of his condition, however, remain a state secret.
Although he is not walking much in public, Chavez insists he is recovering and that he will crush Capriles on election day.
Capriles says the opinion polls are skewed and that his nationwide "house-by-house" campaign is gathering steam and putting him on course to unseat the socialist leader.
He wants to end Chavez's radical, statist policies and install a Brazilian-style "modern left" rule.
The Datanalisis poll showed Capriles up two percentage points from the previous month's survey, and Chavez up 0.7 percentage points.
Another survey on Tuesday - by pollster Gis XXI, which is run by a former Chavez minister - also gave him a healthy lead with 57.8 percent of voter intentions versus 23.0 percent for Capriles.
The two candidates sparred bitterly on Monday over the possibility of a face-to-face televised campaign debate.
Chavez said he would be "ashamed" to square off with a "non-entity" like Capriles, while the opposition flagbearer said the president was better at insulting than debating.
(Writing by Andrew Cawthorne; Editing by Daniel Wallis and David Brunnstrom)