The so-called Waterkloof Four are due to be released on parole on Tuesday.
The correctional services department confirmed at the end of January the group would be released on parole in February.
"Legislation spells out that when an offender completes 50% of their jail term, they can be considered for parole on condition that they completed internal correctional programmes and are well behaved," said spokesperson Manelisi Wolela.
Reinach Tiedt, Gert van Schalkwyk, Christoff Becker, and Frikkie du Preez from Waterkloof were 15 when they committed the acts that led them to be convicted of the murder of an unknown black man and of assaulting another man in a field in Pretoria in 2001. They admitted the assault but have consistently denied killing the other, unidentified man. They were sentenced to 12 years each.
Last year, the high court in Pretoria ordered Tiedt and Van Schalkwyk back to Zonderwater Prison after they were released under correctional supervision. A full bench of judges set aside district magistrate Peet Johnson's ruling of December 15 2011 to convert the men's prison term to correctional supervision. An application had been brought by the minister and the correctional services department commissioner to set aside Johnson's order.
'Ongoing internal investigations'
Correctional services suspended the Zonderwater Prison parole board with immediate effect over its release of two.
"The suspensions relate to the ongoing internal investigations over the erroneous recommendation by the Zonderwater correctional supervision and parole board to convert the custodial sentences of convicted murderers Reinach Tiedt and Gert van Schalkwyk to correctional supervision," said spokesperson Phumlani Ximiya in a statement at the time.
Wolela said the four were well behaved and had completed internal programme. "We have very strict parole conditions, any deviation from those conditions may result in their parole being revoked."