Nelson Mandela will likely greet fans and players for 10 to 15 minutes at the Soccer World Cup opening ceremony before watching the rest of the game from home, his grandson said on 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's president from 1994 to 1999 after spending 27 years in prison during the apartheid system. 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 energise 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.

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." -- Sapa