Former president Nelson Mandela is in good health despite rumours to the contrary, the Nelson Mandela Foundation (NMF) said on Friday.

"The fact is that Mr Mandela is as well as anyone can expect of someone who is 91-years-old and who has lived an active and demanding life as he has," said NMF chairperson Jakes Gerwel.

"He obviously needs to rest more than he has in the past, and indeed to do the things that he enjoys in his well deserved retirement. He therefore recently decided to cut back his engagements even further and spend more time with his family."

Rumours have been abounding that Mandela is gravely ill and, said the foundation: "The endless speculation often leads to intrusive questioning of those around him".

He had always been open about his health and personally made a public announcement in 2001 when he was diagnosed with prostrate cancer.

"People everywhere can therefore be assured that Mr Mandela and his family will continue this trend and will keep the public informed should there be any significant deterioration in his health.

"In the meantime, we appeal to all concerned to respect Mr Mandela's privacy and that of his family."