Vice President Nicolas Maduro broke the news to attendees during Friday night Mass at the military hospital where Chavez was being treated.
"He has a strength superior to the treatments that he is receiving, and he is in a good state of mind," Maduro said.
The government of the oil-rich nation has released few details about Chavez's condition since he began a long series of surgeries and chemo treatments in 2011. He has not been seen in public since December and has been using a respirator.
The Los Angeles Times said Sunday it was believed to be a form of abdominal cancer. Thus far, Chavez has undergone four surgeries and at least one other chemo session.
The government has refused to concede any possibility Chavez's days in power are numbered. But the Times said last week's arrest of a former Caracas borough mayor on influence-peddling charges was seen by some analysts as an attempt to increase Maduro's public stature.
Maduro had called for defendant Leopoldo Lopez to be put on trial just days before he was hauled into court.