The group left Tripoli’s Mitiga airport on Tuesday but the aircraft had a technical problem and had to turn back, UN officials said. They were due to depart again late on Wednesday.
UNHCR previously evacuated more than a thousand refugees and asylum seekers to Niger, but the process was suspended from late February because of delays in resettling them in Western countries.
Several hundred refugees were resettled directly from Libya, but numbers were limited because most Western embassies evacuated Tripoli in 2014.
Another evacuation flight from Libya to Niger is planned for next week, said UNHCR official Omar Bugharsa.