Darfur is the first case the UN Security Council has referred to the new ICC but Sudan has said it would not extradite anyone. Instead Khartoum announced it would hold its own trials of 160 alleged suspects.
In a report in advance of his first appearance before the Security Council on Wednesday, prosecutor Luis Moreno-Ocampo said any Sudanese trial probably would not conflict with an ICC investigation aimed at "prosecuting persons most responsible for crimes".
He said that in Sudan there appeared to be an "absence of criminal proceedings relating to the cases on which the Office of the Prosecutor is likely to focus".
Moreno-Ocampo has received 2500 items, including documents, video footage and interview transcripts as well as a list of 51 suspects, including army and government officials, from a UN-appointed International Commission of Inquiry.
An estimated 180,000 people have died in the Darfur, in Sudan's west, and 2 million have fled their homes to escape slaughter, pillaging and rape in what the US has termed "acts of genocide".
The fledgling ICC, the world's first permanent criminal court, was created to try perpetrators of war crimes, crimes against humanity and genocide. It is a tribunal of last resort when local judicial systems are unable or unwilling to do so.
But Moreno-Ocampo said once he had completed his investigation, his office would determine whether any ICC cases were "the subject of genuine national" prosecutions in Sudan.
The Security Council decided that Sudan over the past two years had not brought suspects to justice and asked the ICC, based in The Hague, Netherlands, to do so instead.
The US, which opposes the court, abstained in the resolution, adopted on 31 March.
Moreno-Ocampo said he had met Sudanese officials in the Netherlands and received information about the country's legal system. He also met officials from the African Union, which has a monitoring force in Darfur.
But he said his investigation required "specific, full and unfettered cooperation of the government of Sudan and other parties in the conflict".
While the prosecutor has set up an investigative team, he gave no indication when he would seek to visit Sudan or whether Khartoum would issue a timely visa.
The ICC, unlike temporary tribunals, has no time limit for its work. Its indictments remain in force until the suspect is tried, dies or runs out of hiding places.
Moreno-Ocampo, 52, an Argentinian, prosecuted generals in his country's "dirty war" in 1985, when wounds from the 1976-1983 government were still fresh. As many as 30,000 people were killed or disappeared.
Meanwhile, on the political front, talks between Sudan's government and two Sudanese rebel groups in Darfur, which were held in Abuja, Kenya, appeared headed for a deadlock, with differences emerging between the latter two, according to Aljazeera.
A rebel group that broke away from Sudan's Liberation Movement (SLM) in Darfur has dismissed the head of the movement, Abd al-Wahid Muhammad Nour.
Aljazeera said quoting the group that it would not recognise any agreement signed by Nour.
SLM's spokesman said there were real divisions within the movement.
The Justice and Equality Movement (JEM), Khalil Ibrahim, underwent a similar split when a faction refused to recognise him as the movement's head.
However, the African Union has rejected the demands of breakway groups and insisted on the continuation of negotiations, Aljazeera added.