President Salva Kiir has criticised the South Sudanese peace mediators for introducing five presidents' post in the proposed government structure.
Speaking at the swearing-in of new Foreign minister Nhial Deng Nhial in Juba, President Kiir lamented the imposition on South Sudan of what he said had not been used in any conflict resolution in the region.
"South Sudan has become a field for experiments. Things that have never been done in any country or government are being tried in South Sudan," President Kiir said.
The five vice-presidents are expected to deputise him in the transitional period.
The posts were proposed at the Khartoum peace agreement, expected to be signed by the South Sudan factions on July 26.
President Kiir, however, said he would accept to ink the deal to help deliver peace to the people of South Sudan.
"People of South Sudan are looking for peace and if that arrangement can bring peace, I am ready to take it," he said.
The South Sudan factions were under pressure to ink the final document within this month.
Mediators have also warned of consequences against the parties rejecting the peace deal.
Several power sharing proposals have been rejected by the parties in the past weeks.