The draft, which was published on Tuesday, states that no law shall be approved which contradicts "the rules of Islam".
That could set Iraq on a course different from what was envisioned when US-led forces invaded the country in 2003.
"Islam is the official religion of the state and is the main source of legislation," the draft reads. "No law that contradicts with its rules can be promulgated."
The document grants the Shia religious leadership in Najaf "independence for its guiding role" in recognition of its "high national and religious symbolism".
Al-Sabah noted, however, that there were unspecified differences among the committee on the Najaf portion.
Those would presumably include Kurds, Sunni Arabs and Shias on the 71-member committee.
During the US-led occupation, key Iraqi Shia and some Sunni politicians sought to have Islam formally designated as the main source of legislation in the interim constitution, which went into effect in March 2004.
Bremer blocked Iraqi move
However, the former US-appointed governor of Iraq, Paul Bremer, blocked the move, saying Islam would be considered "a source" - but not the only one.
The former US governor Paul
Bremer blocked previous moves
At the time, prominent Shia politicians agreed to forego a public battle with Bremer and raise the issue again during the drafting of the permanent constitution.
It could move Iraq towards a more religiously based society than was envisioned by the US that hoped the country would serve a beacon of Western-style democracy in the region.
Members of the constitutional committee, speaking on condition of anonymity, said the draft in Al-Sabah was among several and none would be final until parliament approves the charter by 15 August.
The drafting committee met on Tuesday to discuss federalism, one of the most contentious issues, according to Sunni Arab member Mohammed Abed-Rabbou.
He described the discussion as heated and said no agreement on the issue was reached.
According to Al-Sabah, the draft constitution would declare Iraq a sovereign state with "a republican democratic federal system". However, the word "federal" appears in brackets, indicating some opposition among the committee.
"Islam is the official religion of the state and is the main source of legislation"
Iraq's draft constitution
Sunni Arabs are suspicious that federalism, a prime goal of the Kurds, would lead to the disintegration of the country.Sunni Arab members involved in writing the charter have complained that the Shia and Kurds on the committee are trying to steamroll their version of the draft without proper consultation and discussion.
Parliament speaker Hajim al-Hassani, a Sunni Arab, urged Iraqi media on Tuesday to refrain from publishing supposed texts unless they were released by the constitutional committee.
Resumption of talks
The Sunnis agreed on Monday to resume work on the committee after they walked out in protest and cited security as one of the reasons.
Sunnis had walked out in protest
citing security as one of the reasons
Sunni Arab support is crucial because the charter can be scuttled if voters in three of Iraq's 18 provinces reject it by a two-thirds majority - and Sunni Arabs are reportedly a majority in four provinces.
US officials are anxious for the Iraqis to meet the 15 August deadline as a major step in building a stable, constitutional Iraqi government.
If the deadline is met, voters will decide whether to approve the charter in mid-October and if they go, another general election will take place in December.