A range of observers and stakeholders have called on South Sudan's government and armed opposition to resolve the deadlock over forming a transitional government.

The two sides missed a deadline on Friday to form a transitional government, five months after the two signed a peace deal, throwing into question the future of the deal.

A main sticking point is the creation of 28 states by President Salva Kiir, which the rebel leader Riek Machar opposes. There are further points of contention over cantonment of soldiers and amendment of the constitution to accommodate the peace deal.

South Sudanese activist group Community Empowerment for Progress Organization (CEPO) called on the government and rebels to find a compromise urgently, warning that the peace deal is in danger of falling apart.

"The fear among the citizens for the failure of the peace agreement is growing daily," CEPO said. "Communities are losing trust and confidence on the commitment of the principal partners for smooth implementation of the agreement."

CEPO called on the African Union to facilitate a face-to-face meeting between Kiir and Machar at the continental body's upcoming summit in Addis Ababa next week.

The group urged the AU to ensure that the two men find final solutions to the issue of amending the constitution, the 28 states, timing of the formation of the unity government in regards to amending the constitution, and demilitarization of Juba and establishment of joint integrated police.

Meanwhile, United Nations Secretary Ban Ki Moon called on the parties to overcome their differences. He further urged the African Union, as well as member states of the Intergovernmental Authority on Development (IGAD) to address the political impasse at the upcoming African Union summit.

Ban expressed his concern over the deadlock regarding the 28 states and the parties' failure to meet the 22 January deadline. He stressed that the formation of the Transitional Government is an essential step in implementing the peace agreement and laying the foundation for peace and stability in the country.

Separately, the Troika of US, UK, and Norway told the parties to make immediate efforts to resolve the impasse.

"The Presidential Decree establishing 28 states has created an obstacle to consensus," the Troika said. "It is time for leaders on all sides to put aside partisan bickering and prioritize the interests of the South Sudanese people."