President P.W. Botha, who was hospitalized after suffering a stroke, Thursday named Chris Heunis, a longtime ally and a government minister, as the acting president, Botha's office said.

Heunis, the senior-ranking Cabinet minister, served as acting president for several days last year while Botha was traveling in Europe. It was not immediately clear how long Heunis would remain in the post.Heunis, the minister of constitutional development, is considered a mainstream member of Botha's National Party who would be unlikely to seek any major changes in policy.