The South Sudanese government ended a boycott Tuesday after mediators accepted the participation of its entire delegation in the revitalisation forum.
The second phase of High-Level Revitalisation Forum began on Monday in neighbouring Ethiopian capital Addis Ababa.
But the government delegation skipped the talks when the Igad-led mediation team refused to accept its extra participants having limited the seats of parties to the talks to 12 members each.
The South Sudanese officials had insisted that their delegation included a number of advisers and experts needed to tackle a number of issues being debated in the forum.
But Juba appears to be prepared to throw more spanners in the works after the government spokesperson, Michael Makuei Lueth, said that the President Salva Kiir's administration is not prepared to negotiate issues such as the restructure of government and army.
The second phase of the revitalisation will also discuss the implementation of a permanent ceasefire and deliberate on revised and realistic timeline for the general election.
South Sudan plunged into war in December 2013 when President Salva Kiir accused his former deputy Riek Machar of plotting a coup.
A peace deal signed two years later collapsed in July 2016 when fresh fighting in the capital Juba forced Machar into exile.
The renewed violence spread across the country, and numerous new armed opposition groups have formed, further complicating peace efforts.