"While at times, his condition becomes unstable, the doctors indicate that the former president has demonstrated great resilience and his condition tends to stabilize as a result of medical interventions," the statement reads.
Zuma said that doctors are still working to further improve Mandela's health and keep him comfortable.
He also urged South Africans to pray for Mandela, who is 95 years old.
Zuma will travel to Malaysia Sunday.
The Lifetime Award for Global Peace will be awarded to Mandela by the Mahathir Global Peace Foundation, and Zuma will accept the award on Mandela's behalf.
Mandela was incarcerated for 27 years during the fight to end South Africa's apartheid system before coming the country's first black president in 1994.