Desmond Tutu's tribute to Mandela

This file photo from 1994 shows Nelson Mandela, right, holding hands with Desmond Tutu in Cape Town, South Africa. Picture: AP Photo/The Star Tribune/Jerry Holt

South Africa's archbishop emeritus Desmond Tutu has made an emotional tribute to his late friend Nelson Mandela, calling him an "incredible gift" to the nation, transcending race and class.

Speaking slowly and often on the verge of tears, Tutu said Mandela was "a unifier from the moment he walked out of prison", after 27 years behind bars.

"He taught us extraordinarily practical lessons about forgiveness, compassion and reconciliation."

In a tribute delivered often with closed eyes, the visibly moved fellow Nobel Peace laureate who is seen as South Africa's moral beacon, described Mandela as an "incredible gift that God gave us".

"We are relieved that his suffering is over but our relief is strung in our grief. We pray that he will rest in peace and rise in glory," Tutu said of the 95-year-old's death on Thursday.

But Tutu, known for his frankness even when it came to the nation's beloved icon, said Mandela was not without shortcomings.

"Did he have weaknesses? Of course he did, among them his steadfast loyalty to his organisation and to some of his colleagues who ultimately let him down, retaining in his cabinet underperforming, frankly incompetent ministers."

This had "laid the seeds for greater seeds of mediocrity and corruptibility that were to come", said Tutu, 82, who frequently laments South Africa's post-democratic flaws.

Yet he dismissed fears of "doomsday and disaster" for South Africa on the passing of the man who was behind the country's emancipation from white minority rule.

"Some have suggested that... as he's gone our country is going to go up in flames," Tutu said.

"This is, I think, to discredit us South Africans, to discredit his legacy. The sun will rise tomorrow and the next day and the next. It may not appear as bright as yesterday but life will carry on."

Mandela spent his first night as a free man at Tutu's home in 1990 and he told of poignant interactions with the leader.

Impersonating Mandela's trademark voice, he described how Mandela had organised someone to pay for a driver for Tutu after he had discovered the clergyman had driven himself to his Johannesburg home for a lunch.

"He cared, he really, really cared," said Tutu, struggling to keep his composure.

Calling on South Africans to follow Mandela's example and using his clan name urged them to "let Madiba's dream be our dream".