A healthy sounding President Hugo Chavez called Venezuelan state television from Cuba on Monday to dispel rumours fanned by a nine-day silence that he had died undergoing cancer treatment at a hospital in Havana.

It seems we will have to become accustomed to live with these rumours, because it is part of the laboratories of psychological war, of dirty war, the 57-year-old socialist leader said in the telephone call.

Since leaving for Cuba on April 14 to undergo radiation treatment for an undisclosed cancer, Chavez had only addressed Venezuelans by short messages on Twitter to cheer supporters and hail the advances of his socialist revolution.

His unusually long silence stirred speculation about his health and raised doubts about his political future as he campaigns for re-election in an October 7 vote.

Chavez said the cancer therapy was hard and he needed to rest, but that he was recovering and planned to return to Caracas on Thursday - although he would need another radiation session.

Some people would like to see me leave here sprinting ... not yet, let me recover. I have to rest and look after my diet, the treatment and the hours I keep, Chavez said. These rumours sometimes are damaging.

He said the rumours about his health were so strong they even had his mother worried and he had to call her.

Photos released by the Venezuelan government showed Chavez wearing a track suit and strolling in a garden in Havana with Foreign Minister Nicolas Maduro, playing bowls with his brother, Adan, and kissing a crucifix as he hugged his daughter, Maria Gabriela.

Information Minister Andres Izarra posted the photos on his Facebook page with the title Chavez alive and kicking.

Opposition candidate Henrique Capriles criticized Chavez for running the oil producing nation remotely by Twitter from a Havana hospital bed. One of the president's first acts when he returns will be to sign a new labour law to take effect on May 1.

Chavez's political ally and president of the National Assembly legislature Diosdado Cabello accused the opposition of having a morbid obsession with the former soldier's health.

The truth is that these embittered people don't learn. They've been saying for days that the Comandante died, he said.

The only thing that is lifeless here is that loser, Cabello added on Twitter, referring to Capriles, the opposition's best hope for ending Chavez's 13 years in power.

'GOVERNING BY TWITTER'

Chavez's opponents have criticized him for keeping the country in the dark about the extent of his illness, raising suspicions that his cancer may have spread from an initial baseball-sized tumour that was removed from his pelvis.

Before leaving for Cuba earlier this month, Chavez acknowledged that radiation therapy was physically tiring and he skipped the Summit of the Americas in Colombia this month on the advice of his doctors.

Despite his cancer, Chavez is seeking a new six-year term at an election that is shaping up to be the toughest political fight of his career due to his ill health and a serious opposition challenge.

President Chavez seems to be in a paradoxical situation in which he cannot win the election unless he continues his campaign, but, if he continues, the stress could shorten his life expectancy, preventing him from being the final nominee, Barclays Capital said on Monday.

Capriles, a youthful state governor who is the opposition's unity candidate to face Chavez, sharply criticized the all-dominant leader for not doing his job properly.

Governing by Twitter, approving laws by Twitter without consulting anybody, is an insult to our people. The country's problems cannot be resolved by Twitter, Capriles said.

Chavez's government faces potentially embarrassing accusations about links to drug trafficking from a former Supreme Court justice who fled the country and has reportedly become a U.S. Drug Enforcement Administration informant.

Chavez remains very popular among poorer Venezuelans who have benefited from his social programs, which redistribute some of the country's vast oil wealth.

Almost all recent opinion polls have given Chavez a comfortable double-digit lead over Capriles, and his frequent trips to Cuba for treatment appear not to have changed that.

A survey released on Monday by local pollster Hinterlaces showed 53 percent of voters planning to back Chavez in October, versus 34 percent for Capriles, a 1 percentage point gain for the president since a similar poll last month.

(Additional reporting by Diego Ore; Editing by Daniel Wallis and Christopher Wilson)