Former South African leader Nelson Mandela, 93, was admitted to hospital after doctors advised specialist medical attention for a long-standing abdominal complaint.

"President Jacob Zuma wishes to advise that former president Nelson Mandela was admitted to hospital today, the 25th February 2012," a statement from the presidency said.

"Madiba has had a long-standing abdominal complaint and doctors feel it needs proper specialist medical attention."

The health of the increasingly frail anti-apartheid icon, who is affectionately known as Madiba, sparked national fears after he was hospitalised early last year for an acute respiratory infection.

"We wish him a speedy recovery and assure him of the love and good wishes of all South Africans and people throughout the world," the statement from the presidency said.

"We request that all respect the privacy of Madiba and that of his family during this period."

Presidential spokesman Mac Maharaj told the private eNews channel that Mandela was admitted on Saturday morning and was doing well.

"I can assure you that the former president is in good spirits and well," he said.

Mr Mandela returned to his Johannesburg home last month from his rural home village in the Eastern Cape. He last appeared in public at the final of the football World Cup hosted by South Africa in July 2010.

He won the Nobel Peace Prize in 1993, a year before he was elected the country's first black president in South Africa's first all-race vote and served one term before stepping down in 1999.

Rumours over Mr Mandela's health flare up periodically on social networking sites.

The whispers inspire outpourings of grief for the national hero who is regarded locally and abroad as an icon who walked out of an apartheid prison to lead the nation into freedom.

In December, a local television station aired archive footage of his January 2011 hospitalisation which spurred a series of tweets mistakenly announcing new ill health concerns.

The presidency had to issue an assurance of his health to quell the rumours.

Reuters