Chavez returned to Venezuela from Cuba, where he was treated for cancer, on Monday, but hasn't been seen in public since before his operation Dec. 11.
Information Minister Ernesto Villegas did not indicate the type of treatment Chavez was receiving, but recently said a tube was inserted in the president's trachea to help him breathe, The New York Times reported Friday.
"The respiratory deficiency that arose in the course of the post-operative period persists, and its tendency has not been favorable, for which reason he continues to be treated," Villegas said in a statement.
Chavez was being treated at a military hospital in Caracas, El Universal reported.
"The patient stays in touch with his relatives, the government's political team and [is] in close collaboration with his treating medical staff," Villegas said.
Chavez, who has been in office for 14 years, was re-elected to another six-year term in October 2012.