Zuma made the comment after visiting his predecessor, who is critically ill, The Washington Post reported Thursday.
Referring to Mandela by his clan name, Zuma said, "We are encouraged that Madiba is responding to treatment and urge the public to continue providing support and showering him with love, which gives him and the family strength."
Mandela has been hospitalized since June 8 with a recurring lung infection.
Graca Machel, Mandela's wife, said his positive response to treatment has made her "less anxious," the BBC reported.
She has constantly been at his side in the hospital.
Visitors who have seen Mandela in the past week said he was conscious and responsive.
His 95th birthday is next week.