Cyril Ramaphosa congratulates South Sudan’s new vice-president
He also "welcomed that guns have gone silent and they are working together in co-operation with President Salva Kiir".
Ramaphosa had invited Deng to Tuynhuys "so that we can be briefed about what has been happening in South Sudan".
"The government has become stable‚ the parliament has opened and we were very pleased and heartened to hear all these developments‚" he said after the meeting on Tuesday.
Ramaphosa said a task team would be set up between his office and Deng’s "to work on matters of mutual interest which will be decided on at both government level and our two presidents will then be able to take all these matter to another level".
While Deng said that "more violence is not an option in Africa‚ in South Sudan or anywhere elsewhere in Africa"‚ he had harsh words for the man he replaced‚ Machar.
Machar had‚ as part of a peace agreement‚ returned to Juba and was sworn in as vice-president in April‚ but fled after renewed fighting between the Kiir loyalists and his own supporters two months later.
Deng replaced Machar when the latter ignored an ultimatum to return to Juba.
"The dilemma is not with Salva Kiir or Taban Deng‚" said Deng. "The dilemma is Riek Machar himself.
"He has been asked to return to Juba‚ but how is he going to return? Is he going to return with the same crisis that brought fighting in Juba‚ like, for example‚ moving with huge forces‚ parallel armies.
"Riek is impatient‚ he is not waiting for elections‚ he sees himself as a president-in-waiting‚ he is seeing himself [as] a parallel president. So if he has removed himself from all those difficulties‚ if he goes back to Juba a peaceful person‚ then he is welcome to Juba. Otherwise‚ we are telling him the option is not going back to war."