A delegation of former rebels from southern Sudan has arrived in Khartoum, for talks on implementing the peace deal signed in January.
The SPLM team is led by former rebel commander James Wani
The priority for all parties will be to agree on a new constitution - a process expected to take about six weeks.
This will lead to a coalition cabinet between Khartoum and the former rebels.
The peace deal put an end to a 21-year civil war between the Muslim-dominated government and fighters from the Christian and animist south.
The BBC's Jonah Fisher in Khartoum says implementation of the agreement is behind schedule.
Both the former rebels of the Sudan People's Liberation Movement (SPLM) and the government have devoted time to consolidating political support.
The former rebels have been working to transform themselves into a political party, while the government has been trying to get other northern groups included in the process.
The 100-strong SPLM delegation arrived in the capital on Sunday, and is headed by former rebel commander James Wani.
Under the January peace agreement, the current government and the SPLM are to share power and oil revenues.
Sudan's civil war claimed more than two million lives and forced at least four million from their homes.
A separate conflict in the Western region of Darfur has triggered fresh fears of a humanitarian disaster.