President Hugo Chavez of Venezuela will not take the oath for a new term in office on Thursday.
National Assembly Speaker Diosdado Cabello announced on Tuesday that Mr Chavez would be sworn in at a later date before the Supreme Court, according to Article 231 of the Constitution.
Mr Chavez, 58, is in hospital in Cuba after cancer surgery and has suffered complications caused by a lung infection. He has not been seen in public since an operation on 11 December.
The opposition has called for the Supreme Court to rule on what should be done if Mr Chavez is absent.
According to the constitution, the National Assembly Speaker should act as caretaker president until new elections are held within 30 days.
The government insists that the inauguration is a mere formality for an incumbent leader.
The BBC reports that Mr Chavez has been president since 1999.
In May 2012, Mr Chavez said he had recovered from cancer, after undergoing surgery and chemotherapy in 2011 and a further operation in February 2012.
However, last December he announced he needed further cancer surgery in Cuba and named Vice-President, Nicolas Maduro as his preferred successor.