By Diego Ore and Daniel Wallis
CARACAS (Reuters) - Venezuelan President Hugo Chavez maintained a 15 percentage-point lead over his opposition rival Henrique Capriles in a closely watched poll published on Monday, less than three months ahead of an October 7 presidential election.
The June survey by respected local pollster Datanalisis showed 46.1 percent of voters backing Chavez and 30.8 percent for Capriles, while the rest were undecided or did not respond.
Chavez is seeking a new six-year term at the helm of South America's biggest oil exporter, but he has been battling cancer for a year and not able to match the intensive campaigning of his younger opponent, a basketball-loving former state governor.
The 57-year-old socialist remains popular in his 14th year in power thanks to huge state spending on social programs and the enduring emotional connection that even his fiercest critics concede he shares with the country's poor majority.
Capriles, 40, has been drawing big crowds while projecting an image of youth and energy. Some recent polls have shown him narrowing the gap with Chavez -- one had them neck and neck -- but the new poll on Monday showed Chavez keeping a solid lead.
His 15.3 percentage-point advantage was slightly narrower than the 15.9 percent gap recorded by Datanalisis in May, but still within the margin of error of 2.7 percentage points.
"As the campaigns heat up, it's normal for the numbers to begin to get closer," Datanalisis president Luis Vicente Leon told reporters. "Undecided voters continue to be the ones who will define the election."
Most of Venezuela's best-known pollsters give Chavez a double-digit lead over Capriles, who is promising to end the president's radical, statist policies and set up a Brazilian-style "modern left" administration.
Chavez has staged a remarkable recovery from an undisclosed type of cancer that was diagnosed last year and left him all but silent and off the political stage for weeks at a time.
RALLIES 'FORGED' DOCUMENTS
He says he is completely recovered after three operations, and in recent weeks he has sharply increased his number of public appearances. Last week, he launched a series of big street rallies featuring his typically thundering speeches.
On Sunday, Capriles led a large march through the capital Caracas that sought to highlight a key concern of many voters: insecurity and a crime rate that is one of the worst in the world.
Over the weekend both sides focused on a spat over the armed forces after Capriles issued a video message to troops and his team released what it said was a leaked Defense Ministry order prohibiting his speech from being played on military bases.
Chavez said that document had been forged as part of the opposition's "dirty war." He compared it on TV with what he said was a real order from the ministry and suggested Capriles may have committed a crime by publishing it.
Asked about Chavez's comments, Capriles said "threats and intimidation" would not stop the opposition.
He has kept up a blistering pace since winning the opposition's primaries in February. On Sunday he told the rally he had visited 53 towns in just the last 15 days, and his aides say his efforts will bear fruit before election day.
Capriles has adopted "The Hurricane of Progress" as a nickname, while Chavez styles himself as the "Bolivarian Hurricane" - which refers to the president's idol and South American independence hero Simon Bolivar.
Unable to match Capriles' tireless crisscrossing of the country because of his delicate health, Chavez is increasingly leaning on the powerful, quasi-religious emotional ties he enjoys with Venezuela's long-marginalized working classes.
A new campaign video tells voters that "they too are Chavez," and at a rally in the western city of Barquisimeto on Saturday he said -- in typically colorful fashion -- that even the youngest Venezuelans knew who to vote for.
"The vast majority of children know, from the depths of their genetic inheritance, that the route to the fatherland is with Chavez and victory on October 7!" he shouted, to cheers from thousands of red-clad supporters. "Even though they don't know how to talk yet, if they could, they would say 'Chavez!'"
(Editing by Cynthia Osterman)