In late April, Zuma and top officials in the African National Congress, the anti-apartheid movement turned ruling party, were photographed with an unsmiling Mandela looking exceedingly frail at his Johannesburg home.
The visit prompted allegations that the embattled party was exploiting Mandela for political gain.
The ANC, facing elections next year, has lost much of its Mandela shine amid widespread corruption, poverty and poor public services.
Mandela has not been seen in public since the World Cup final in South Africa in July 2010 and has not been politically active for years.
“I think there will be concerns from outside South Africa that Mandela is seen as the glue that holds South Africa together,” analyst Daniel Silke said. “But I think that this is something long gone, frankly.”
After serving just one term as president, Mandela turned to the battle against HIV/AIDS and conflict resolution, before stepping out of the public eye at age 85.
Ordinary people, young and old, on Tuesday left messages of support outside his home in northern Johannesburg.
A couple wearing T-shirts bearing the words: “We love you Papa Mandela,” placed a teddy bear in a similar shirt outside the gate.
Others wrote messages of support on small stones outside the high security walls, while a group of schoolchildren stopped by to sing for him to “get well.”