JOHANNESBURG – South Africa's anti-apartheid icon Nelson Mandela was Sunday discharged from hospital where he has been treated since June 8 for a recurring respiratory illness, the presidency said.

Despite his release, questions remain about the health of the 95-year-old Nobel laureate who has been in and out of hospital for a year and who, the presidency said, remains in "critical" condition.

"Former President Nelson Mandela has this morning, 1 September 2013, been discharged from the Pretoria hospital where he has been receiving treatment," said a statement from the presidency.

It is said his condition "remains critical and is at times unstable."

An ambulance with police escort was seen arriving at his suburban home, north of Johannesburg, shortly after 0900 GMT.

Officials said Mandela will receive the same intensive care from his Johannesburg home.

"If there are health conditions that warrant another admission to hospital in future, this will be done," the presidency said.

President Jacob Zuma's office said the elderly statesman has been treated by "a large medical team from the military, academia, private sector and other public health spheres."

His release came after the presidency on Saturday denied reports that Mandela had been discharged from hospital.

"Madiba is still in hospital in Pretoria, and remains in a critical but stable condition," Zuma's spokesman said in a statement, denying reports from several news organisations that he had left the facility.

"At times his condition becomes unstable, but he responds to medical interventions."

Since his admission, South Africans have been united in prayer for a speedy recovery of the country's first back president.

Global leaders and local politicians have also been sending him messages of support during his lengthy treatement at a private hospital in the capital Pretoria.

Mandela has faced several health scares in recent years and his lung problems date back to his 27 years in apartheid jail.

Madiba, his clan name by which he is lovingly known in the country, has been in and out of hospital since last year, with lung related complications.

"Despite the difficulties imposed by his various illnesses, he, as always, displays immense grace and fortitude," according to Zuma's office.

In December, he spent nearly three weeks in hospital where he was treated for a lung infection and gall stones.

His latest hospitalisation has been his longest since he walked free from jail in 1990 and went on to become the country's first leader to be elected in all-race elections.

Speculation has arisen often as few details have been released about his condition, which has been largely described as "critical but stable" and updates on his health have been infrequent.

In June, the revered leader was said to be on life support but has recently been reported to be breathing on his own.

Family members including his wife Graca Machel and ex-wife Winnie Madikizela-Mandela have been visiting his bedside since his admission.

Mandela retired from public life in 2004, and has spent his time between his rural home in the Eastern Cape region and Johannesburg.