South Sudan President Salva Kiir has turned down the regional block Inter-governmental Authority on Development (Igad) proposal to work together with rebel leader Dr Riek Machar.
South Sudan Information Minister and government spokesman Michael Makuei on Thursday said President Kiir had accepted Dr Machar' return to Juba but will not participate in the would-be transitional government until democratic elections are held.
"President Salva Kiir is not ready in any way to work again with Dr Riek Machar in the next transitional government... we have had enough of him," Mr Makuei told journalists in Addis Ababa.
Earlier in the day, Dr Machar, the Sudan Peoples' Liberation Movement in Opposition (SPLM-IO) chief, proposed change of tack to the peace process and adopt the model that led to the 2005 Comprehensive Peace Agreement.
Dr Machar said the Agreement, which led to the secession of South Sudan from Sudan in 2011, allowed the warring parties to discuss amongst themselves how to solve their issues as mediators recorded areas of agreement.
The two long-standing rival will again meet next week in the Sudanese capital Khartoum in a new round of talks as the outcomes of the first face-to-face meeting in nearly two years on Wednesday night remain elusive.
The last meeting between Kiir and Machar immediately preceded the outbreak of deadly fighting in the South Sudanese capital Juba in July 2016.
Defeated, Machar fled into exile in South Africa where he was placed under de-facto house arrest.
The two men are central to the civil war in the world's youngest country, which has killed tens of thousands and driven a third of the country's 12 million people from their homes.
Kiir's December 2013 accusation that Machar was plotting a coup signalled the start of the war.
Efforts to revitalise the 2015 agreement resulted in a ceasefire in December which lasted just hours before warring parties accused each other of breaking it.