Venezuelan president Hugo Chavez's ill health is likely to prevent him from being able to take his fourth oath of office before the National Assembly on 10 January.

Chavez, who won his fourth term after last October, is fighting a severe infection in his lungs and receiving treatment in a Cuban hospital. The infection arose following a cancer operation in December.

However, his vice-president, Nicolas Maduro, has claimed that Chavez will be able to be sworn into office by the Supreme Court later, with no consequences for missing his inauguration.

Appearing on Venezuelan television on Friday evening, Maduro said: "The constitution establishes that as a formality he should be sworn in before the National Assembly on 10 January."

hugo chavez tumor cancer

Chavez has not been seen or heard from since he went to Cuba for his operation

"But already on 10 January, the new constitutional period begins and he continues his functions and he can take the oath of office, as stipulated in the Constitution, at the moment that he goes before the Supreme Court of Justice."

According to CNN, Venezuela's constitution is unclear on the exact procedure for Chavez to be sworn in by the Supreme Court.

There is no specific conditions as to whether the Supreme Court inauguration should happen prior to the 10 January, when the constitution says Chavez should be inaugurated, whether Chavez needs to be in the country or not, or who should preside over the country while Chavez is incapacitated.

Opponents of Chavez have called for a new round of elections if the 58-year-old is unable to attend the ceremony next week.

The president has not been seen or heard from since he travelled to Cuba for surgery last month, prompting speculation about the severity of his condition.

But his information minister, Ernesto Villegas, has accused opponents of manufacturing a "psychological war" on the administration with the "ultimate aim of destabilising the Bolivarian republic".

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  • A man passes in front of a graffiti of Venezuelan President Hugo Chavez in Caracas, on January 2, 2013. Chavez is conscious and fully aware of how 'complex' his condition remains three weeks after difficult cancer surgery in Havana, the Venezuelan president's handpicked successor, Vice President Nicolas Maduro, said Tuesday. Maduro, who is returning to Caracas today on January 2, provided no specifics about Chavez's condition but defended the government's efforts to keep the public abreast of the president's health. Chavez underwent his fourth cancer-related surgery three weeks ago in Havana and has been bed-ridden ever since. (LEO RAMIREZ/AFP/Getty Images)

  • Supporters of Venezuela's President Hugo Chavez hold his picture during a vigil in Managua, Nicaragua, Sunday Dec. 9, 2012. (AP Photo/Esteban Felix)

  • Supporters of Venezuela's President Hugo Chavez gather during a vigil in Managua, Nicaragua, Sunday Dec. 9, 2012. (AP Photo/Esteban Felix)

  • A man wearing a T-shirt with a portrait of Venezuela's President Hugo Chavez prays during a vigil in Managua, Nicaragua, Sunday Dec. 9, 2012. (AP Photo/Esteban Felix)

  • A person holds up an image of Venezuela's President Hugo Chavez among religious images during a demonstration in support of him at the Simon Bolivar square in Caracas, Venezuela, Sunday Dec. 9, 2012. (AP Photo/Fernando Llano)

  • A woman holds a picture of Venezuela's President Hugo Chavez as supporters gather at Simon Bolivar square in Caracas,Venezuela, Sunday Dec. 9, 2012. (AP Photo/Fernando Llano)

  • A woman reacts during a demonstration in support of Venezuela's President Hugo Chavez at the Simon Bolivar square in Caracas, Venezuela, Sunday Dec. 9, 2012. (AP Photo/Fernando Llano)

  • A woman wears a pin with a picture of President Hugo Chavez that reads in Spanish 'love is repaid with love' as Venezuelan residents gather in support of Chavez in front of the embassy of Venezuela in Havana, Cuba, Sunday, Dec. 9, 2012. (AP Photo/Ramon Espinosa)

  • A woman reacts a supporters of Venezuela's President Hugo Chavez gather at the Simon Bolivar square in Caracas,Venezuela, Sunday Dec. 9, 2012. (AP Photo/Fernando Llano)

  • Women react as they gather at Simon Bolivar square in support of Venezuela's President Hugo Chavez in Caracas,Venezuela, Sunday Dec. 9, 2012. (AP Photo/Fernando Llano)

  • Venezuelan residents in Cuba gather in support of President Hugo Chavez in front of the embassy of Venezuela in Havana, Cuba, Sunday, Dec. 9, 2012. (AP Photo/Ramon Espinosa)

  • A Venezuelan resident in Cuba wearing a T-shirt with an image of Venezuela's President Hugo Chavez and carrying a Cuban flag participates in a demonstration in support of him in front of the embassy of Venezuela in Havana, Cuba, Sunday, Dec. 9, 2012. (AP Photo/Ramon Espinosa)

  • A boy gestures during a rally in support of Venezuelan President Hugo Chavez, in Caracas on December 9, 2012. (JUAN BARRETO/AFP/Getty Images)

  • Former Venezuelan Vice President Elias Jaua (C) speaks during a press conference in support of Venezuelan President Hugo Chavez, in Caracas on December 9, 2012. (JUAN BARRETO/AFP/Getty Images)

  • A supporter of Venezuelan President Hugo Chavez attends a rally in Caracas on December 9, 2012. (JUAN BARRETO/AFP/Getty Images)

  • Supporters of Venezuela's President Hugo Chavez rally in Caracas on December 9, 2012. (JUAN BARRETO/AFP/Getty Images)

  • A supporter of Venezuela's President Hugo Chavez shows his picture during a rally in Caracas on December 9, 2012. Chavez admitted a relapse of his cancer late Saturday and designated vice president Nicolas Maduro as his heir apparent in case 'something happened' to him. (JUAN BARRETO/AFP/Getty Images)

  • Supporters of Venezuela's President Hugo Chavez rally in Caracas on December 9, 2012. Chavez admitted a relapse of his cancer late Saturday and designated vice president Nicolas Maduro as his heir apparent in case 'something happened' to him. (JUAN BARRETO/AFP/Getty Images)

  • Supporters of Venezuela's President Hugo Chavez show a placard with his image during a rally in Caracas on December 9, 2012. Chavez admitted a relapse of his cancer late Saturday and designated vice president Nicolas Maduro as his heir apparent in case 'something happened' to him. (JUAN BARRETO/AFP/Getty Images)

  • Supporters of Venezuela's President Hugo Chavez show his picture during a rally in Caracas on December 9, 2012. Chavez admitted a relapse of his cancer late Saturday and designated vice president Nicolas Maduro as his heir apparent in case 'something happened' to him. (JUAN BARRETO/AFP/Getty Images)

  • A statuette depicting Venezuelan President Hugo Chavez is seen on display at a shop in Caracas on January 7, 2012. The church weighed in with four days to go before President Hugo Chavez, who is in Cuba recovering from cancer surgery, is supposed to be sworn in to a new six year term. (Leo Ramirez/Getty Images)