The call by Zain al-Abidin bin Ali came a day after Libya announced the end of its presidency of the group, insisting the North African body had failed to achieve its goal of cooperation.
Bin Ali expressed his concern to the Libyan leader about the decision, then contacted Algerian President Abd al-Aziz Bouteflika to press for reform of the 16-year-old body.
In a statement on Wednesday, the Libyan foreign ministry said "the march of the union has stalled and violations are many ... therefore, Libya has decided to leave this union to its people".
The ministry did not make it clear whether Libya would withdraw from the union, which groups Algeria, Libya, Mauritania, Morocco and Tunisia. The chairmanship rotates among the five heads of state.
The union was founded in 1988 with an aim of promoting cooperation among its members, but has been dogged by disputes.