The 79-year-old was admitted for a cardiac weakness, the Sapa news agency quoted the manager of Netcare Akasia Hospital as saying. Botha was said to be in a stable condition.
Botha served as foreign minister up to the end of apartheid and was appointed mines and energy minister after South Africa’s first all-race elections in 1994 under the government of Nelson Mandela, a post he held until 1996.
In 2000, he quit the National Party that governed during apartheid to join Mandela’s African National Congress (ANC).
Botha had been considered a liberal in National Party ranks, and was severely reprimanded by then State President P.W Botha for having said in 1986 that a black president may one day rule South Africa.
An accomplished negotiator, he served as ambassador to the United Nations and the United States in the mid-1970s.
He abandoned politics in 1996 when the National Party withdrew from a government of national unity with the ANC.