"The next constitution of Tunisia won't mention a state with Islam as its religion, but of belonging to an Ummah (community) which has Islam as its religion," Kais Saied told journalists at Tunis airport on Tuesday.
"The Ummah and the state are two different things."
Saied took delivery of the draft text on Monday, a key step in his drive to overhaul the Tunisian state after he sacked the government and seized far-reaching powers last July in moves opponents called a coup.
Sadeq Belaid, the legal expert who headed the drafting committee, had told AFP in an interview earlier this month that he would remove all reference to Islam from the new document in a challenge to Islamic parties.
His comments, partly referring to Saied's nemesis Ennahdha, an Islamic-inspired party which has dominated Tunisian politics since 2011, sparked a heated national debate.
The first article of Tunisia's 2014 constitution -- and its 1959 predecessor -- defined the North African country as "a free, independent and sovereign state. Islam is its religion and Arabic is its language".
The 2014 document was the product of a hard-won compromise between Ennahdha and its secular rivals three years after the uprising that overthrew dictator Zine El Abidine Ben Ali.
The new text, produced through a "national dialogue" excluding opposition forces and boycotted by the powerful UGTT trades union confederation, is meant to be approved by Saied by the end of June before being put to voters next month.
That is a year after the former constitutional law professor sacked the government, later consolidating his power grab by dissolving parliament and seizing control of the judiciary.
Many have criticized his moves, warning he is returning the country to autocracy.
Saied has long called for a presidential system that avoids the frequent deadlock seen under the mixed parliamentary-presidential system.
Asked about that issue on Tuesday, he said: "Whether the system is presidential or parliamentary is not the question.
"What counts is that the people has sovereignty. There's the legislative function, the executive function and the judicial function, and separation between them."