Maduro, who showed a photo of a white-plaster wall with marks that appear like eyes and a nose, said Chavez's face had briefly appeared to workers building a new subway line in Caracas in the middle of the night.
Speaking on state television, the president said: "My hair stands on end just telling you about it. Who is that face? That gaze is the gaze of the fatherland that is everywhere around us, including in inexplicable phenomena."
Maduro - who was elected president in April after the death of Chavez - has previously spoken of seeing the spirit of his idol several times, including in the shape of a bird.
Venezuela's electoral authority is to carry out a full audit of electronic votes cast in the country's presidential election.
The announcement, reported by Reuters, comes hours before Nicolas Maduro was due to be sworn in as Hugo Chavez's successor after a narrow victory on Sunday.
The US had already called for a recount of the closely fought poll.
Mr Maduro was declared the winner by the country's National Electoral Council by 262,000 votes from 14.9 million cast by Venezuelans.
Venezuelan acting president Nicolas Maduro has said a centuries-old curse would fall on the heads of those who do not vote for him in next week's election to pick a successor to late leader Hugo Chavez.
Maduro's invocation of the "curse of Macarapana" was the latest twist in an increasingly surreal fight between him and opposition leader Henrique Capriles for control of the South American OPEC nation of 29 million people.
"If anyone among the people votes against Nicolas Maduro, he is voting against himself, and the curse of Macarapana is falling on him," said Maduro, referring to the 16th-century Battle of Macarapana when Spanish colonial fighters massacred local Indian forces.
To the cheers of thousands of supporters, acting Venezuelan President Nicolas Maduro officially registered his candidacy today for the upcoming elections.
The 50-year-old arrived to the National Electoral Council driving his own bus to register his candidacy.
"I am going to accomplish his orders (referring to Chavez) with the biggest love that he cultivated in our hearts. I am not Chavez, but I am his son and together with the people, we are Chavez," Maduro said after registering his candidacy.
Both Maduro and opposition leader Henrique Capriles have begun Venezuela's election race with scathing personal attacks on one another.
Maduro, who was sworn in as acting president after Chavez succumbed to cancer last week, is seen as the favourite to win the April 14 election, bolstered by an oil-financed state apparatus and a wave of public sympathy over Chavez's death.