Prime Minister-designate Saad Hariri secured a victory for his March 14 alliance in the June parliamentary elections over the March 8 opposition that includes Hezbollah lawmakers.
Lawmakers had agreed to a power-sharing agreement in the next government, allocating 15 seats to March 14, 10 to March 8 and five for allies with Lebanese President Michel Suleiman.
That formula was disrupted when Druze leader Walid Jumblatt abruptly left March 14 recently, saying his "necessary" alliance with the Western-backed alliance had ended.
Hariri, for his part, hoped talks with Aoun, leader of the opposition Free Patriotic Movement, would lead to some Cabinet developments, though negotiations appear to have suffered a major setback, Lebanon's Daily Star newspaper reports.
March 14 lawmakers are reportedly upset over Aoun's insistence, along with Hezbollah, that his son-in-law and caretaker Telecommunications Minister Jebran Bassil retain his position despite losing in the June vote.
Meanwhile, Aoun hopes to nominate his own Maronite ministers to the Cabinet, which may put government negotiations in a deadlock with Maronites in the March 14 alliance.
Hariri pledged to act quickly to form a new unity government when March 14 emerged victorious in June.