Mandela has not made a public appearance since the 2010 World Cup final in Johannesburg [EPA]

A South African presidential spokesman has said that Nelson Mandela has been released from hospital.

Spokesman Mac Maharaj said the former president was released on Sunday after undergoing a laparoscopy. During the procedure, surgeons make an incision in the belly to insert a thin, lighted tube to look at abdominal organs.

Earlier in the day, South African President Jacob Zuma said "doctors have assured us that there is nothing to worry about" and that Mandela is in good health.

Mandela, who spent 27 years in prison for fighting racist white rule, became South Africa's first black president in 1994 and served one five-year term. He last appeared in public in July 2010.

Mandela underwent the minor surgery to determine the cause of a stomach complaint and the 93-year-old "is as fine as can be at his age," South Africa's defense minister said.

The military took charge of Mandela's health care after he spent several days in a private hospital last year with a respiratory infection. Officials have not disclosed where he is being treated this time to protect his privacy.

On Sunday, well-wishers prayed for Mandela at Regina Mundi church in Soweto, a former centre of anti-apartheid protests and funerals.