Some SPLM officials have already begun work in Khartoum, but the group's official arrival has been delayed as the movement prepares its transformation to political party from rebel group.

Deng Goc Ayuil, the most senior SPLM official in Khartoum, told Reuters the high-level 70-member delegation would likely arrive next week but by the end of the month at the latest.

"Tomorrow I will go to Nairobi to make preparations for their arrival," he said, adding he would then move from Kenya to SPLM areas in the south to meet with other officials.

"Right now they are holding workshops to prepare the members of the delegation for what they will be doing in Khartoum," he said, adding that the first task would be to agree an interim constitution for Sudan.

He said the SPLM had opened six offices in Khartoum and at least 10 others all over government areas of Sudan, and was planning to inaugurate two more offices in the north this week.

"We need more to deal with the registration of new members," he said.

He could not give figures for the overall number of registrations, but said in January after the signing of the deal, 1,100 people signed up in Khartoum.

Ayuil said the SPLM would hold its first general assembly since the peace deal with about 10,000 members in a town near the Kenyan border around mid-April to decide on the leadership of the SPLM and who would take which posts in government.

The southern conflict, which claimed 2 million lives, broadly pitted the Khartoum-based Islamist government against the mostly Christian and pagan south, complicated by issues of oil, ethnicity and ideology.