The agency said almost 100,000 migrant workers, mostly from Egypt and Tunisia, had fled Libya in the past week and many remained stranded at the Libya-Tunisia border as Libyan customs officers deserted their posts on Sunday.
"We call upon the international community to respond quickly and generously to enable these governments to cope with this humanitarian emergency," said Antonio Guterres, the United Nations High Commissioner for Refugees (UNHCR).
Meanwhile two ferries docked late Sunday with some 300 people, including the ambassadors to Libya from Malta and Portugal, on the Mediterranean island of Malta. As the closest European Union member state located just 350 kilometres (220 miles) north of Libya, it has become a key hub in the desperate scramble to get foreigners out of Libya.
Malta's Prime Minister Lawrence Gonzi said his island nation had received some 8,000 people since the Libyan crisis began and he feared there could be an even greater exodus.
"There could be an escalation