Chavez, 58, remains firmly in control of the South American country even though he has not been seen in public since he went to Cuba for surgery a month ago. The Venezuelan government has not disclosed the type of cancer from which Chavez is suffering.
Members of his ruling United Socialist Party carried photographs of the absent president in the streets and many wore T-shirts reading: "I am Chavez," The Wall Street Journal reported.
Wednesday, key opposition leader Henrique Capriles said a Venezuelan Supreme Court ruling letting Chavez begin his new term in absentia was politically motivated.
The court's ruling was intended "to resolve the problem" in the ruling United Socialist Party of a growing power struggle between Vice President Nicolas Maduro and National Assembly President Diosdado Cabello, Capriles said.
The power struggle has "totally paralyzed" the government, he said. Opposition leaders had called for the court to declare Chavez "incapacitated," which would have opened the way for new elections.
Maduro is the man Chavez said he wanted as his party's candidate in case he himself couldn't continue as president. Chavez appealed to voters to vote for Maduro. Cabello is a former vice president with close ties to Venezuela's military but has few ties to the Cuban revolution.
Chavez -- who declared himself fully recovered from his unspecified cancer July 9 -- flew to Cuba Dec. 10 for additional cancer surgery. He later developed a severe pulmonary infection that has resulted in a "respiratory insufficiency," the government said last week.
The last official statement on Chavez's health Monday said he was still fighting a post-surgical lung infection.
Chavez won election to a fourth term Oct. 7.