The text, which received the green light from the government earlier this month, must be approved by three-fifths of lawmakers in Chad’s National Assembly.
It comes amid growing political tensions in Chad, ranked by Transparency International as one of the world’s most corrupt nations, as opposition groups boycotted a forum last month discussing the proposed changes.
A Western ally in combating jihadism in the volatile Sahel region, cash-strapped and poverty-stricken Chad has endured two years of severe recession worsened by a slump in oil prices.
The changes will increase presidential terms to six years with a limit of two terms. The current mandate is five years with no limits on re-election.
It does not include provisions for the creation of a post of vice president, contrary to what was proposed at a national forum on the reforms in March.
Deby, 65, is serving his fifth term, which runs until 2021. He has insisted the changes are necessary.
The influential Catholic Church has however warned that a new constitution “seriously risks distorting the rules of the democratic game.”
Opposition groups have called for the text to be put to a referendum.
Deby, who has been named in a corruption probe in the United States, has said that elections on hold since 2015 will take place this year.