South African President Jacob Zuma said on Tuesday that anti-apartheid hero Nelson Mandela was getting the best medical care although his condition showed no improvement.

Appearing on state television, Zuma said he had confidence in Mandela's medical team which was doing its best.

Zuma said the former president, "the real father of democracy in South Africa," was in a serious but stable condition.

Mandela is spending his fourth night in the Mediclinic Heart Hospital in Pretoria, where he is receiving intensive treatment for a recurring lung infection.

"Yesterday I met the team of doctors who are treating him. They gave me a very thorough briefing and really I was very confident that they know what they are doing and they're doing a very good job," Zuma said.

"Whilst it is very serious, but he's stabilized and we are all praying for him really to recuperate quickly.

"And I'm sure, knowing him as I do, he's a good fighter and he'll be with us very soon."

Zuma was expected to visit Mandela on Tuesday, according to an announcement by the presidency on Monday. But the presidency said on Tuesday that Zuma cannot visit Mandela at this time as he is in Cape Town preparing for the Budget Vote of the presidency.

The latest update came as concern was mounting over the condition amid press reports that Mandela's condition was worse than what was officially stated.

Mandela was whisked from his Johannesburg home to the hospital early Saturday after his condition deteriorated.

This was the fourth time since December last year that Mandela was hospitalized.

His frequent hospital stays have raised grave concern about his health.