Makaziwe Mandela, the eldest daughter of the ailing 94-year-old, has accused the intense media interest in Mr Mandela's condition of disrespecting her father and her family.
"We don't mind the interest, but I just think it has gone overboard. You can't even enter the hospital or go out because they are making such a nuisance," Ms Mandela said in an interview with South Africa's state broadcaster SABC.
"When Margaret Thatcher was sick in hospital, I didn't see this kind of media frenzy around [her]," she said.
"There's sort of a racist element with many of the foreign media, where they just cross boundaries," she added, after making her way through the scrum of camera crews and reporters gathered outside the hospital.
"It's truly like vultures waiting when the lion has devoured the buffalo, waiting there for the last of the carcass.
"That's the image we have as a family. If people say they really care about Nelson Mandela, then they should respect that. They should respect that there is a part of him that has to be respected."
Speaking about her father's condition, Ms Mandela said: "I won't lie, it doesn't look good."
But she went on to say that when she spoke to him, she could see him respond and try to open his eyes.
"He's still there," she said.
Jacob Zuma, South Africa's president, has paid a second visit in 24 hours to Mandela and was told by his doctors he had improved overnight.
"He is much better today than he was when I saw him last night. The medical team continues to do a sterling job," Zuma said in a statement released by his office. The presidency said Mandela remains "critical but is now stable".
Barack Obama, who is due to visit South Africa this weekend, said his thoughts and prayers were with the Mandela family and the South African people.