The United Nations' Libya envoy Abdoulaye Bathily said on Monday he was concerned about "unilateral and competing initiatives" by Libyan institutions to rebuild Derna, where a destructive flood killed thousands of people last month.

"Unilateral efforts are counterproductive, deepen the existing divisions in the country, impede reconstruction efforts and are at odds with the outpouring of solidarity, support and national unity shown by Libyan people," he said in a statement.

On Sunday, the parliament-appointed government said it was postponing an international conference it had planned to hold on reconstruction for Derna.

The Government of National Unity in Tripoli has also said it plans to hold a reconstruction conference.

Analysts have said control over Derna's reconstruction, which could bring large sums in finance and coordination with foreign powers, may become a major new arena for conflict between Libyan factions.