South Africa's peace icon Nelson Mandela is facing a long and uncertain road to recovery, despite his return home from nearly three months in hospital, medical experts said on Monday.

The 95-year-old anti-apartheid hero is receiving intensive care for a respiratory illness at his Johannesburg home where he returned Sunday after 86 days in a Pretoria hospital.

"It's going to be a difficult process, he has a lot factors stacked up against him," said Elvis Irusen, who heads the department of Pulmonology at the University of Stellenbosch.

Mandela, he added, also has a long history of pulmonary illness to overcome, and his advanced years will make that recovery even more difficult.

"It does not look good," said Irusen.

Details of Mandela's recurring lung infection have been not revealed since he was admitted to hospital on June 8, fuelling speculation about his longterm health.

The Nobel peace laureate's condition has been largely described as "critical but stable" and updates on his health have been infrequent.

In the past few months, the revered former leader was once said to be on life support and there were unconfirmed reports he had to be resuscitated.

Irusen said chances were high that the frail statesman is on a ventilator to aid his breathing.

"That comes with a lot of problems as well; a ventilator could make a person prone to infections," he added.

Government has said he could be taken back to hospital "if there are health conditions that warrant another admission," insisting that he will be treated by a large medical team from the military, private and public health sector.
His home has been reconfigured for the treatment.

Another pulmonary specialist, Umesh Lalloo, also spoke of a bleak prognosis.

"He has had a lot of health problem and his advanced age does not make it easier for him,"

"In this case the progress of recovery is poorer," he said.

In 1988, while serving his 27-year prison term, Mandela was diagnosed with early stage tuberculosis.

Two litres of fluid were drained from his chest and he spent six weeks recuperating in hospital.

Despite the experts' gloomy outlook, ordinary South Africans who have been praying for Mandela's recovery were on Sunday relieved that he was home.

His suburban Johannesburg home is still far from Qunu, a village where he grew up and he has long expressed a wish to live out his life.

Mandela is admired throughout the world for his lifelong sacrifice in fighting the brutal regime of racial segregation installed with apartheid in 1948, and for his role in bringing multiracial democracy to South Africa, a country many feared would disintegrate into civil war.

Mandela became South Africa's first black president in 1994, after leading talks that ended white minority rule and put the ruling African National Congress in power.

He only served a single four-year term, stepping down in 1999.