Hariri stepped down as prime minister-designate last week as opposition leaders rejected his decision to move ahead with a Cabinet without their consent.
It is expected Hariri will be reappointed as his March 14 coalition secured the majority in the Lebanese Parliament following June elections. Michel Aoun, the leader of the opposition Free Patriotic Movement, however, said he would not back Hariri's reappointment, Lebanon's Daily Star newspaper reports.
"Whoever wishes to nominate Saad Hariri, let him do, and whoever refrains to do so, I would act with him following my designation like he acted with me prior to it," said Hariri.
Hariri reached a power-sharing agreement with opposition leaders in the March 8 slate in the wake of the June elections. Political analysts, however, had predicted it would be difficult for Hariri to form a unity government because of the complex nature of Lebanese politics.
At the center of the issue was the appointment of caretaker Communications Minister Jebran Bassil with the opposition Free Patriotic Movement for the next Cabinet. Hezbollah and its allies lobbied for his appointment, though Bassil did not win in the June elections.