Chad’s parliament approved a new constitution on Monday expanding President Idriss Déby’s powers and potentially allowing him to stay in office until 2033.
The vote, which was boycotted by most opposition lawmakers, eliminates the post of prime minister.
Critics say the move to a fully presidential system is aimed at entrenching Mr Déby’s power.
Another change is to the length of presidential mandates.
The current term is five years long with no limits on re-election.
The new constitution imposes a six-year mandate, and re-instates a maximum limit of two terms which had been scrapped in a 2005 referendum.
The changes will not be applied retroactively.
This means President Déby could serve two terms after the next election in 2021, staying in post until 2033.
The constitution now awaits President Déby signature for it to enter into force.
Tensions are growing in Chad after opposition groups boycotted a forum last month discussing the proposed changes.
AFP also reports that two human rights activists who wanted to stage a sit-in in front of parliament yesterday ahead of the vote were arrested and later released.
Tchindebbe Patalle, a spokesman for the National Union for Development and Renewal (UNDR) opposition party, is quoted by the news agency as saying all opposition groups had “wanted to demonstrate outside parliament to protest against the vote but the security forces are posted all around”.
Chad is ranked by Transparency International as one of the world’s most corrupt nations.