Moren-Ocampo has called for the arrest of Ahmed Harun, Sudan's humanitarian affairs minister, who faces charges of war crimes and crimes against humanity.
He said he was concerned that silence by world leaders "has been understood in Khartoum as a weakening of international resolve".
"It is time to break the silence," he said.
Moreno-Ocampo said Harun, who is suspected of involvement in the murder, rape, torture and persecution of civilians in Darfur, is now in charge of the millions of people he forced out of villages into camps.
"Ahmed Harun is not protecting the camps, he is controlling them. He must be stopped. He must be arrested. The international community must be consistent in their support of the law."
The ICC wants Friday's UN meeting, chaired by Ban Ki-moon, the UN secretary general, and Alpha Oumar Konare, the African Union chairman, to be used to push the Sudanese government to arrest Harun.
But bringing to justice those most responsible for killing over 200,000 people and uprooting more than 2.5 million during the four and a half-year conflict is not on the agenda for the meeting.
Instead, ministers from 26 countries have been invited to discuss international support for new negotiations with Khartoum, the deployment of a 26,000-strong AU-UN force in Darfur and the expansion of humanitarian assistance.
"World leaders have to understand that if the justice component process is ignored, crimes will continue and affect the humanitarian and security operations in Darfur," Moreno-Ocampo said.
Postponing Harun's arrest, he said, would mean "there will be no solution in Darfur" but Moreno-Ocampo also expressed hope that the UN secretary-general's talks with Omar al-Bashir, the Sudanese president, earlier this month might "bear fruit".