Bloemfontein - The safe release of an employee being held hostage is of primary importance, the Mangaung Correctional Centre said on Wednesday.
Security services company G4S Africa head Andy Baker said the hostage situation was still ongoing on Wednesday afternoon.
Four inmates took a woman guard hostage on Wednesday morning, a local radio station reported earlier.
G4S Africa manages the prison under contract for the correctional services department. Baker said contingency measures at the prison designed to deal with hostage situations had been activated. The company said all other prison operations were stable.
Recently, more than 300 members of the Police and Prisons Civil Rights Union were dismissed at the prison for taking part in an illegal strike.
Sapa