Former President FW de Klerk says in a statement that there’s currently no immediate threat to his life.
He has been diagnosed with mesothelioma, a type of cancer that affects the tissue that lines the lungs.
The former President’s foundation says he will start a course of immunotherapy next week.
Eighty-five-year-old De Klerk headed the white minority government until 1994.
He shared the Nobel Peace Prize with the late former President Nelson Mandela, but his role in the transition to democracy is highly contested more than 20 years after the end of apartheid.