CARACAS: Venezuelan President Hugo Chavez is still in charge and mulling political, social and economic policies even as he receives a new round of chemotherapy, his vice president said Saturday.

Vice President Nicolas Maduro said the 58-year-old socialist leader, who is convalescing in seclusion at a Caracas military hospital, had sent "guidance" to his cabinet as recently as Friday.

"He is staying informed and in charge as the chief who was ratified by our people various times," Maduro said during an event broadcast on state-run television.

The opposition, however, says the government is lying about Chavez's condition and doubts Maduro's claim that Chavez held a five-hour meeting with his cabinet on February 22, giving orders in writing because a tracheal tube hinders his speech.

Maduro cast the doubts aside and repeated that the meeting had taken place, insisting that the president had sent further instructions the following day, before offering fresh guidance on Friday.

The leftist leader's chosen successor Maduro showed a dossier Chavez had requested, containing "political, social and economic actions" to "continue strengthening the economy to face the economic war of the parasitic bourgeoisie".

He said the "central document" will be sent to Chavez, adding that the government was "respecting his treatment" and "not acting in an invasive way in his treatment".

Chavez, who was first diagnosed with cancer in the pelvic region in June 2011, underwent a fourth round of surgery in Cuba in December. The government has never disclosed the exact nature, location and severity of the cancer.

Maduro revealed for the first time late Friday that Chavez had began a new cycle of chemotherapy in January and decided to return to Caracas last month to continue a "more intense" phase of treatment.

Chavez was in "good spirits" but fighting for his life, Maduro said.

One of Chavez's daughters, Maria Gabriela, responded Saturday to the publication online of a picture of her looking sad during mass.

"Sadness? I can't be happy when my dad is sick! But I continue to cling to my God," she wrote on Twitter.

"At the next mass I will have to dance and laugh! I always thought that a mass was something something serious! People are very crazy," she wrote.

In Bolivia President Evo Morales, a close Chavez ally who visited Venezuela late last month and made an unsuccessful attempt to visit him in hospital, also offered an insight on the situation.

Speaking to reporters in the city of Cochabamba, Morales indicated that the Venezuelan president's condition was unstable and prone to sudden changes.

"According to his doctors and family members there are moments when he is feeling well and strong, but quickly problems appear and he suffers something like a relapse," the Bolivian president said.

The once omnipresent Venezuelan leader has not been seen in public in almost three months. Only four pictures were released, on February 15, showing him smiling from his Havana hospital bed with his two daughters.

Around 50 university students have spent every night this week chained to each other in the middle of a Caracas street, demanding that the government "tell the truth" about Chavez.

The government has accused the opposition and "fascist" foreign media of spreading rumours about Chavez to destabilize the nation, which sits atop the world's largest proven oil reserves.

"We want to see Chavez recover and healthy, and we want him to be in peace, doing the treatment that needs to be done," said Foreign Minister Elias Jaua.

"Those who don't want Chavez to recover are those who use blackmail, criminal pressure, miserable pressure that we will not cede to," Jaua said.

Maduro, meanwhile, accused opposition leader Henrique Capriles of "conspiring" against Venezuela during trips to the United States and Colombia, and warned him not to "violate the rule of law".

He said Capriles, the Miranda state governor who lost to Chavez in the October presidential election, had met with "paramilitaries" in Colombia and was now in the United States.

The vice president said Capriles travelled to Miami and New York this weekend and was planning to meet Roberta Jacobson, the US State Department's top official for Latin America.