While former president Nelson Mandela's condition remains critical but stable, at times it becomes unstable, the presidency said on Saturday.
"While at times, his condition becomes unstable, the doctors indicate that the former president has demonstrated great resilience and his condition tends to stabilise as a result of medical interventions," spokesperson Mac Maharaj said in a statement.
Maharaj said doctors were working hard to effect a turnaround, improve Mandela's health and to keep him comfortable.
"President Jacob Zuma urges South Africa to continue praying for Madiba and to keep him in their thoughts at all times," Maharaj said.
Zuma will be travelling to Malaysia on an official visit on Saturday.
The visit was aimed at boosting social, political and economic ties between the two countries.
Zuma would receive a Lifetime Award for Global Peace awarded to Mandela, on his behalf, by the Mahathir Global Peace Foundation. – Sapa