"Based on Article 76 of the Constitution, I call [on the president] to appoint a candidate for the prime minister’s post within 15 days," al-Halbousi said, as quoted by Al-Arabiya broadcaster.
According to the broadcaster, political circles have been pushing for the appointment of former Oil Minister Ibrahim Mohammad Bahr al-Ulloum.
On Tuesday, media reported that Salih had started the first round of consultations with the country’s political blocs to choose a new head of government after Adel Abdul Mahdi announced his resignation amid the ongoing unrest in the country.
Since October, Iraq has been gripped in nationwide anti-government protests, with thousands demanding the government's dismissal, economic reforms and an end to corruption. The unrest has left reportedly over 400 people killed and thousands more injured in clashes with armed forces.