CARACAS: Venezuelan President Hugo Chavez is able to work on government issues and is "very energetic" despite being hospitalised and breathing through a tube, a top aide said Saturday.

The 58-year-old president has not been seen or heard from since Monday, when he returned to Caracas from cancer surgery in Cuba.

"The president continues to breathe through a tracheal tube, but he is able to communicate with us through written notes and give us instructions," Vice President Nicolas Maduro told local television.

He said he spent more than five hours with Chavez in his hospital room on Friday, and was able to discuss several issues, specifically military affairs and the economy.

"He was very energetic, had a lot of spirit and vitality, and that's what we wanted to tell the people despite the late hour," Maduro said.

"We have reviewed a number of subjects, and he told us about being extremely happy to be in Caracas, the city of his heart."

Since his last surgery, the only photos released of Chavez came out almost a week ago. He was seen bed-ridden but smiling, looking through a newspaper with two of his daughters at his side.

At the Caracas military hospital where Chavez is said to be continuing his convalescence, soldiers are on guard outside to keep out journalists and curious onlookers.

Chavez had declared himself free of cancer after earlier rounds of surgery and went on to win another six-year term in October elections.

But he later suffered a relapse and after the latest surgery in Havana on December 11, he was too sick to return to Venezuela for his scheduled inauguration on January 10.

The inauguration has been postponed indefinitely, prompting the opposition to cry foul. Vice President Nicolas Maduro, Chavez's handpicked heir, has essentially been running the country in Chavez's absence.