ICRC president Jakob Kellenberger told reporters on Wednesday that his organisation had visited more than 700 prisoners of war (POW) in SPLA jails in southern Sudan, but did not specify how many will be released or when.
"We have completed arrangements for transporting the POWs held by the SPLA," he said, following talks with several Sudanese government ministers.
He did not say whether the Sudanese army had SPLA members in detention.
The ICRC chief also said he had proposed to the Khartoum government "an expansion of the ICRC activities and assistance in Darfur," the conflict-hit western region of Sudan.
State Foreign Minister Najib al-Khair Abd al-Wahab told reporters the ICRC has been invited to join a multilateral aid structure for Darfur.
"There is a joint mechanism of the Sudanese government, the United Nations, the European Union, the US Agency for International Development and NGOs coordinating humanitarian assistance to Darfur, and the ICRC has been invited to join this mechanism which meets regularly and discusses the situation transparently," said Abd al-Wahab.
About one million people are estimated to have been affected by the fighting between government forces, militia and rebels in the Darfur region, following a year-long rebellion over alleged government neglect of the impoverished region neighbouring Chad.
"We have completed arrangements for transporting the POWs held by the SPLA"
Several hundred thousand people have fled their homes, many of them across the border, and aid agencies have warned that they cannot reach victims of the conflict inside Sudan who are thought to be short of food, shelter and medical care.
In Geneva, the ICRC said earlier that Kellenberger would meet with Sudan's President Umar al-Bashir during his two-day trip to Khartoum which ends on Thursday.
Kellenberger is expected to fly to Kenya later this week to meet the key players in peace negotiations there on the conflict in southern Sudan, including SPLA leader John Garang.