"I hope it does not last long and I can return soon," the 56-year-old president said in a televised speech shortly before leaving Caracas. "I have to say I am optimistic. I have never loved life the way I am loving it now."

On Friday Chavez asked the National Assembly for permission to travel to Cuba so he can continue treatments after his June 20 operation in Havana.

"I will travel to Havana to begin what we have called the second stage of this slow and complex process of recovery, which is going well," Chavez said Friday.

Though the National Assembly unanimously approved his travel request, which is needed for the President to leave the country for more than five days, opposition leaders say it is unconstitutional for Chavez to continue to exercise executive authority from Cuba.

"When the president leaves the country, the vice president must assume the chief executive role. It is their duty," said opposition lawmaker Hiram Gaviria.

"The health of the country must be put above the president's health. We must be serious. We believe he should not hold office from Havana," added another opposition lawmaker, Carlos Berrizbeitia.

But other lawmakers say Chavez should continue his chief executive role, because he has the mental and physical capabilities to do so.

Chavez, in power since 1999, is his party's candidate for the 2012 presidential election, where he will be seeking a third six-year term in office. On Saturday his supporters accused political foes of encouraging a coup.

Critics of the president have demanded details of his cancer as well as answers to why he cannot be treated in Venezuela, where authorities say they have created a quality health care system.

The Venezuelan government has not explained the extent of Chavez' cancer or whether the tumour is malignant.

Cuba, the America's only one-party communist regime, is Chavez's closest regional ally.

Copyright AFP (Agence France-Presse), 2011