President Salva Kiir has sacked the Deputy Minister of Foreign Affairs, Dr Cirino Hiteng, through a presidential decree.
The reason for the dismissal is unclear.
However, Dr Cirino took part in the 56th Extra-Ordinary Session of the IGAD Council of Ministers which demanded that South Sudan open the Juba International Airport and hand over the security to UNMISS.
IGAD also demanded that the UN intervene militarily in South Sudan.
Dr Cirino signed the communique as part of the council, the National Courier reported. His replacement is yet to be named.