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

Mandela's home has been reconfigured for the treatment and he receives the same level of intensive care from doctors and nurses back home.

The South African government has said he could be taken back to hospital if there are health conditions that warrant another admission.

"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.

Irusen said chances were high that Mandela 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.

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

Another pulmonary specialist, Umesh Lalloo, also spoke of a bleak prognosis. "He has had a lot of health problems and his advanced age does not make it easier for him, in this case the progress of recovery is poorer," he said.

The Nobel peace laureate's condition has been largely described as critical but stable. 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.

Despite the experts' gloomy outlook, South Africans who have been praying for Mandela's recovery, welcomed his discharge from the hospital on Monday.

"We were worried at the time he was at the hospital. Because he is the man who offered himself for us," said 46 year-old domestic worker Thembisa Mbolambi.

"He's the father of the nation," added gardener Harrison Phiri.

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.

Source: Agencies