The trip by members of the rebels' peace negotiating team is a "gesture of goodwill" before next month's meeting between SPLM/A leader John Garang and First Vice President Ali Uthman Taha.
This is according to rebel spokesman Yasir Saeed Arman who was quoted by Khartoum dailies.
The delegation will meet with various political parties, including the ruling National Congress, and civil groups, Arman was quoted as saying by the independent Akhbar Al Youm daily.
The visit is intended to lay the groundwork for the SPLM/A to declare itself a political party amid growing signs the war is drawing to a close and alert rebel supporters in the capital to operate as a party, he said.
He said that the delegation would leave for the capital as soon as it received final government approval, adding that they would be accompanied by officials from an unnamed neighbouring country to guarantee their safety.
The SPLM/A has already initiated contacts with Khartoum-based political groups to open consultations on establishing a national political consensus, he said.
The government and the SPLM/A rebels on Friday agreed to extend an ongoing ceasefire by two months, two days before the peace talks resume in Naivasha, Kenya.
Government officials reportedly welcomed the SPLA visit to Khartoum as "a positive step."
"It is a positive step and will have a tremendous effect in the process of confidence-building and normalisation of relations between the two parties," a senior official was quoted as telling the independent Al Rai Al Aam, which is close to government circles.
"It is a positive step and will have a tremendous effect in the process of confidence-building and normalisation of relations between the two parties"
Senior Sudanese official
The spokesman for Khartoum's delegation to the peace talks taking place in Kenya, Sayyed al-Khatib, also told the independent Al Ayam daily he welcomed the visit, but said the government was "still waiting for an answer" to its request to visit SPLM/A-held areas in the south.
The SPLA rebels have fought Khartoum forces since 1983 to end domination of the mainly Christian and animist south by the Muslim north.
The war has killed at least 1.5 million people and displaced more than four million others.
Both sides are due to resume peace talks in Kenya from 30 November, amid heightened expectations and repeated promises that a final peace accord will be reached by the end of the year.
Taha and Garang are expected to join the talks on 5 December.