Former South African President Nelson Mandela has spent a second day in hospital in a "serious but stable" condition with a renewed lung infection that has triggered worldwide concern for the anti-apartheid icon.

Doctors say there has been little change in the condition of the 94-year-old leader, and he continues to be in a serious but stable state.

Mandela was yesterday rushed to a Pretoria hospital, after his health took a turn for the worse at his Johannesburg home, where he was recovering from a lung infection after being released from hospital on April 6.

This is Mandela's third hospital visit in seven months.

Meanwhile, local media reported that the doctors treating him have advised Presidential spokesman Mac Maharaj not to tell the public that he is getting better for now.

"I questioned the doctors. I said how is he? They said: Look, yes, he is able to breathe on his own. Be concerned, but don't be hysterical about it. Also don't tell the public that he is getting better," the Sunday Times quoted Maharaj as saying.

International concern around the latest hospital stay of the Nobel Peace Prize Laureate, who will turn 95 next month, is being tempered by a statement from his long-time friend and associate Andrew Mlangeni, saying "God must have his own way".

"We wish Madiba (Mandela's clan name by which he is affectionately known) well, but I think what is important is that his family must release him so that God may have his own way. (The family) must release him spiritually and put their faith in the hands of God. Once the family releases him, the people of South Africa will follow.
We will say thank you God, you have given us this man, and we will release him too," Mlangeni told the Sunday Times.

Mandela's wife Graca Machel cancelled a trip to London to address the World Hunger Summit, to be at her husband's bedside.