Correctional Services said that “matters are under control” at Johannesburg’s Sun City Prison on Wed.
Appointed finance and community development minister in July 2000 following the country's bloodiest and most divisive general election campaign since independence two decades ago, Simba Makoni is widely liked and respected.
Even back then opinion polls suggested that Makoni was the most serious challenger to Mugabe's leadership among ordinary Zanu-PF members - he has a reputation for integrity.
By Zanu-PF standards, Makoni reached high office at a relatively young age. At independence, he was appointed deputy minister of agriculture. He was only 30 years old.
While the party old-guard were fighting the liberation war in the 1970s, Makoni was studying chemistry in Britain, gaining a BSc and a PhD.
But as well as being a student, he went on to represent Zanu-PF in Europe.
When he became "too hot to handle" for Mugabe and his cronies, he was dumped.
He became executive secretary of the Southern African Development Community, (SADC), a job which he says required "a fine balance between high principles and pragmatism".
In the job, Makoni gained a great deal of international experience and exposure, and returned to Zimbabwe from Botswana to go into business.
Makoni has more than 20 years' experience in business and general management, development policy formulation and strategic planning, international diplomacy, regional and international trade and investment.
He is the managing director for Makonsult, a consulting practice focusing on policies and strategies that bear on business and politics in eastern and southern Africa.
Makoni has been involved in the development of public policies regarding trade, economic development and communications for the southern African region in many capacities, beginning as a member of the parliament of Zimbabwe.
In his first spell in government he served as minister of youth, sport and culture; minister of industry and energy development and minister of agriculture.
Makoni has a BSc (Hons) in Chemistry and Zoology from Leeds University, UK; and a PhD, Medicinal Chemistry, from Leicester Polytechnic, UK. - BBC and Internet