The statue of Mandela, also known as Madiba in his home country, is scheduled to be unveiled on December, said Arts and Culture Minister Paul Mashatile at a business briefing in Johannesburg.
"We take this opportunity once again to wish Tata Madiba well as he recovers from home," Mashatile said. "Even in sickness, Tata Madiba continues to unite our nation and remains an enjoining symbol of our freedom and democracy."
Mandela, 95, was released Sunday from a hospital in Pretoria after months of treatment for a respiratory illness. Doctors said his condition "remains critical and is at times unstable," but they feel he can receive the same level of treatment at his home.
The Union Buildings were designed by British architect Sir Herbert Baker in 1908, with construction beginning in 1909, a government statement said.
Mandela, South Africa's first democratically elected president, was inaugurated at the buildings, which serve as the seat of the government.