The 57-year-old socialist leader was first diagnosed with cancer in the pelvic region in mid-2011. He wrongly declared himself cured at the end of that year before having a recurrence of the disease in February.

But after repeated cycles of treatment in Cuba and Venezuela, Chavez is once again declaring himself fully fit at a crucial time when his health is the main wild card before the October 7 presidential vote.

Perceptions of Chavez's ability to campaign for the election, and govern afterwards, are crucial among voters in what could be one of Venezuela's tightest elections of recent times.

At a four-hour news conference that offered more evidence of Chavez's increasing energy levels, he promised to begin campaigning on the streets with a series of caravans in provincial Venezuela from Thursday.