Nelson Mandela holds the World Cup trophy in 2004, after FIFA announced that South Africa would host the 2010 tournament. ((Michael Probst/Associated Press))

Nelson Mandela will likely greet fans and players for 10 to 15 minutes at the World Cup opening ceremony before watching the rest of the game between South Africa and Mexico from home, his grandson said Tuesday.

"We believe that maybe before the game we could bring him to the game just to greet the players and greet the fans," Nkosi Zwelivelile Mandela said.

The 91-year-old Mandela was South Africa president from 1994 to 1999 after spending 27 years in prison during the apartheid era. He attended the 1995 Rugby World Cup final in Johannesburg, and any possible appearance during Friday's ceremony at Africa's first soccer World Cup would energize the nation.

There have been doubts Mandela would make an appearance because of his advanced age. He was a key factor in South Africa's winning bid, but has made few public appearances in recent years.

On Tuesday, Mandela made a trip to his office to catch a glimpse of an exhibition of works by a local South African artist, inspired and completed by children of Mvezo village in the country's south, where Mandela was born.

Walking with a help of a cane and appearing frail but happy, Mandela looked at the neat rows of 32 framed and limited edition prints adorning the walls at the entrance of a low red-brick building in a leafy Johannesburg neighbourhood, according to the photographs provided by the Nelson Mandela Foundation.

Madiba magic

The broad-brushed 32 paintings depict 11 joyful and dancing football players, representing the competing soccer nations against a background of their respective national flags. An Africa-shaped heart pulsates in their bodies. All the originals were signed by Mandela.

Mandela has a reputation for inspiring teams to victory with his presence, known as the "Madiba magic."

It was his attendance at the 1995 final at Ellis Park, when South Africa surprisingly beat New Zealand following years of exile from international sport, that was seen by many as the moment when South Africans were truly united.

Mandela took over as president four years after being released from jail, and will be remembered for his role in changing the fate of many South Africans by fostering democracy in the country.

Nkosi said the family has had "to play a protective role in ensuring that we do not open him up to dangers" because of his age.

"To have him sit the entire 90 minutes of soccer would really impact his state of health, because it is winter after all, and we have to guard against that," Nkosi said. "As South Africans, we wish him to live many more years to come."