Former South African president Nelson Mandela is still unable to speak but uses facial expressions to communicate, his ex-wife has told a local newspaper.

Winnie Madikizela-Mandela said the 95-year-old remained "quite ill" but she dismissed speculation that he was on a life support machine.

In September Mr Mandela returned home after nearly three months in hospital with a recurring lung infection.

The government has said his condition is critical and sometimes unstable.

He is no longer talking "because of all the tubes that are in his mouth to clear [fluid from] the lungs", Ms Madikizela-Mandel told South Africa's Sunday Independent newspaper.

"He can't actually articulate anything... He communicates with the face, you see. But the doctors have told us they hope to recover his voice."

"I have heard this nonsense that he is on life support - he is not," she added.

"It is difficult for him. He remains very sensitive to any germs, so he has to be kept literally sterile. The bedroom there is like an ICU [intensive care unit] ward."

Mr Mandela has been receiving intensive care at his home in a suburb of Johannesburg, which has been specially adapted for his care.

The Nobel Peace Prize laureate is revered around the world for leading the fight against white minority rule and preaching reconciliation with the white community despite being imprisoned for 27 years.

Correspondents say the presidency has been keen to reassure not just the Mandela family but the nation that he is no more vulnerable at home than in hospital. It has called for Mr Mandela's privacy and dignity to be respected.