The first evacuation flight from Libya to Rwanda is scheduled for Thursday, arriving at night in Kigali.
They will be housed in a transit centre in Rwanda before being resettled elsewhere unless they agree to return to their home countries.
A subsequent flight carrying 125 people is planned for "between 10-12 October".
A group of 75 African refugees and asylum-seekers is expected to be airlifted from Libya to Rwanda on Thursday, a UN official said, the first of what could be thousands relocated under a new programme.
Earlier this month, Rwanda signed a deal with the African Union (AU) and the United Nations refugee agency UNHCR agreeing to take in African refugees and asylum-seekers stranded in Libya.
The Rwandan government has said it is prepared to accommodate as many as 30,000 evacuees, although the plan is for the programme to unfold in batches of 500 to prevent the country of 12 million from feeling overwhelmed.
"The first evacuation flight from Libya to Rwanda is scheduled for tomorrow (Thursday), arriving at night in Kigali," the UN official told AFP Wednesday via email.
"This first flight under the recently set-up Emergency Transit Mechanism is planned to have 75 people of concern (refugees or asylum seekers) on board."
The official added that a subsequent flight carrying 125 people is planned for "between 10-12 October".
They will be housed in a transit centre in Rwanda before being resettled elsewhere unless they agree to return to their home countries.
In the chaos that followed the fall and killing of former dictator Moamer Kadhafi in a 2011 uprising, Libya became a key transit point for sub-Saharan African migrants seeking to embark on dangerous journeys to Europe. The UN says some 42,000 refugees are currently in Libya. Rwandan President Paul Kagame first offered to take in Africans stuck in Libya back in November 2017, the same month a CNN report showed what appeared to be a slave market there. The issue took on new urgency in July when more than 40 people were killed in an air strike on a migrant detention centre in the Libyan town of Tajoura. The UN has been criticised for its handling of a transit mechanism for evacuees from Libya established in 2017 on the other side of the continent, in Niger. The facilities there have struggled with overcrowding and the slow pace of resettlement. But UN and Rwandan officials say they have learned from Niger's experience. The AU, the continental bloc headquartered in Addis Ababa, hopes other member states will follow Rwanda's lead and welcome African refugees and asylum-seekers stranded in Libya. So far, though, no similar arrangements have been announced.