CARACAS, Venezuela — President Hugo Chávez, who shocked the nation by revealing that he had a cancerous tumor removed and would “continue battling,” could legally keep governing Venezuela from his seclusion in Cuba for as long as six months if necessary, his vice president said Friday.

The statement by the vice president, Elías Jaua, a loyal supporter of Mr. Chávez who has said he has no plans to replace the president temporarily, will almost certainly intensify concerns here over a power vacuum as Mr. Chávez recovers from cancer surgery in a Cuban medical complex.

In the few weeks the president has been out of the country, a bitter dispute between his followers and the political opposition has erupted over whether the Constitution allows Mr. Chávez, 56, to lead from abroad during his convalescence.