Some delegates to the government talks had earlier suggested the Abuja meeting would be held on June 1.
The rebel groups have committed themselves to resuming talks without conditions, although the Justice and Equality Movement (JEM) said it may need security guarantees on the ground in Darfur before negotiations restart.
Officials from JEM and the Sudan Liberation Movement/Army (SLM/SLA) were in Tripoli but did not attend the meeting, which was restricted to government officials.
Leaders from Libya, Sudan, Chad, Nigeria, Egypt, Eritrea and a high-level representative of Gabon met to push for a settlement of the crisis, in which more than 2 million people in Darfur have been displaced.
In a joint declaration, the participants rejected non-African intervention in the western Sudanese region, while boosting AU monitoring forces. They also committed themselves to helping improve the humanitarian situation.
The Tripoli declaration also called for bringing to justice those responsible for crimes in Darfur, but rejected sending anyone to the International Criminal Court (ICC) in The Hague.
"The question of crimes and justice tribunals has been decided by the leaders ... it will be handled in an African way and under the leadership of the African Union," Guba said.
The conflict broke out two years ago when rebels took up arms against the Sudanese government, complaining of discrimination. Khartoum is accused of retaliating by arming militias who burned villages and killed and raped civilians.
At least 180,000 people have died from violence, hunger and disease.
A ceasefire signed in April 2004 has not held and Abuja peace talks sponsored by the African Union have stalled with no meetings taking place since December.
A U.N. Security Council resolution recently referred Sudanese accused of war crimes to the ICC.
Sudan says the resolution provides the option to actually hold any trials inside Africa's largest country.