Maduro spoke of Chavez's condition at the opening of a preschool named after the president's maternal grandmother, in the city of Sabaneta, Barinas state, the president's birthplace.
Maduro said he conversed with Chavez prior to leaving for Chile to attend the first Summit of Latin American and Caribbean States (CELAC) and the European Union (EU), and that Chavez showed great strength and optimism.
Chavez, whose prolonged absence has mobilized the conservative opposition, relayed a warning to Venezuelans to stay alert to any right-wing attempts against his government, said Maduro.
"He told us: 'Don't let down your guard, be careful, warn the people, because there is still a long way to go to consolidate the nation,'" Maduro said.
Named in honor of Rosa Ines Chavez, the Mama Rosa Early Education Center is housed in the president's childhood home.
"That boy who was educated here in these streets became a world leader," Maduro said at the inauguration of the school.
Also attending the ceremony was Adan Chavez, governor of Barinas state and a brother of Hugo Chavez's, who recalled " Grandmother taught us to read from a very early age. When Hugo and I went to school, at the age of six, we already knew how to read and write, and that's what grandma Mama Rosa made sure of."
Prior to leaving for Cuba, Chavez urged Venezuelans to vote for Maduro should he become incapacitated and new elections are called.