CARACAS (AFP) - The health of Venezuelan President Hugo Chavez has evolved in a "favourable" way in recent days, though he still requires treatment for respiratory failure, Communications Minister Ernesto Villegas said.

"Despite his delicate health state since his complex surgery on Dec 11, his general health has improved in recent days and the president is in strict compliance with his medical treatment," Mr Villegas said in a statement broadcast on radio and television.

Earlier on Sunday, however, former vice-president Elias Jaua said the leader is "fighting for his life" after cancer surgery in Cuba,

"The situation is complex and delicate, but it is true that Hugo Chavez has fought and is fighting for his life," Mr Jaua said during a meeting in Caracas of the ruling United Socialist Party.

Mr Chavez has been out of the public eye since undergoing surgery in Havana on Dec 11. It is the fourth such operation in the 18 months since his condition was made public.

The uncertainty surrounding his condition has unsettled Venezuela. The government was forced to postpone the president's scheduled inauguration last Thursday, as it became clear that he could not attend.

Authorities insist the country's constitution allows Mr Chavez to take the oath of office at a later time. But the opposition has objected, calling for a medical board to review the absent leader's health - a demand rejected by the Supreme Court, which said the delayed swearing-in was constitutional.