Speaking at a formal ceremony in the capital Pretoria, Mandela's widow Graca Machel said: "I was numb but now looking back I can imagine him tall and proud walking and all of them rising to receive him, beaming his contagious smile, embracing each one of them and feeling -- yes that's the time he has to unite with them."
The South African government organised the official observance of the death anniversary in Pretoria, where stories of Mandela's memorable life are shared, the official SA News reported. The ceremony was followed by an interfaith service at Freedom Park, an open air memorial, also in Pretoria.
Other events are also due to take place over the weekend and beyond, including artistic performances, as a way of remembering and celebrating the former president, often called the father of the nation and who led the country out of the apartheid era after enduring 27 years in prison.
Motorcyclists across the country have been called upon to dedicate their traditional Sunday morning rides to the anti-apartheid hero.
Apartheid struggle veteran Ahmed Kathrada said the latter would be remembered for his humanity, courage and friendship.
"To me, he was an elder brother and I miss him not only as a political leader but I miss him as an elder brother," said an emotional Kathrada.
During the wreath laying ceremony, Machel and the Mandela families were the first to lay a wreath next to the Mandela statue followed by Mandla Mandela and veterans.
Defence Minister Nosiviwe Mapisa-Nqakula laid a wreath on behalf of the South African government.
In June this year, the UN General Assembly introduced the "United Nations Nelson Rolihlahla Mandela Prize" as a tribute to the achievements and contributions of the late South African leader.