He was speaking in Malaysia after receiving the Lifetime Award for Global Peace from the Mahathir Global Peace Foundation on behalf of Mandela.
"This award comes at an opportune moment," Zuma said.
"Former president Mandela is still in hospital receiving treatment and remains in a critical but stable condition."
Mandela is being treated for a recurring lung infection in the Mediclinic Heart Hospital in Pretoria.
He was admitted on June 8.