Representatives of nations supporting the mediation process of the South Sudan peace talks have begun pushing the idea of a face-to-face meeting between President Salva Kiir and rebel leader Riek Machar.

EU envoy Alexander Rondos said such a face-to-face between the rivals was essential to end the "cycle of vengeance" and killings that has left a ceasefire agreed in January in tatters, Reuters reported.

“The situation is now so combustible that it has all the ingredients of an all-out civil war in which the consequences could end up being genocidal,” said Rondos.

Rondos was in a delegation of African, US, British, Norwegian, UN and IGAD envoys who met Machar at his base in South Sudan recently.

The group told Machar that he and Kiir should meet to rein in their fighters and end the bloodshed. “We await his positive reaction,” Rondos said of Machar's response to the proposal.

Reuters also quoted Rondos as saying there were ongoing contacts with Kiir and the government in Juba, and a similar proposal would be put to the president. He said he believed Kiir also understood the “time was right” for a meeting under IGAD auspices.

“Both sides are being given a very clear message that they cannot afford anymore to use diversionary tactics, political or otherwise, and that the time has come for the principals (Machar and Kiir) to be seen together and agree on a way to prevent further violence,” Rondos said in a telephone interview from Europe.

The diplomat did not give details of where or when such a meeting might take place.