Chiwenga, aged 61, a former military general who led the coup that ousted long-time ruler Robert Mugabe last November, is widely seen as the power behind Mnangagwa and the front-runner to succeed him.
According to the Sunday reports, Chiwenga is receiving his treatment at Cape Town’s Groote Schuur Hospital in the Western Cape Province.
Mnangagwa, who took over from his mentor Mugabe, appointed Chiwenga vice president after the coup and retained him following his disputed 30 July election win.
Speculation about Chiwenga’s health began circulating two weeks ago when the vice president, frequently seen at Mnangagwa’s side, was absent from public view, press reports said.