One of the poorest and most troubled countries in the world, the landlocked nation has been gripped by conflict and political turmoil for most of its history after independence from France in 1960.
Touadera's rivals say he wants to remain "president for life" — under the increasingly visible protection of private Russian mercenary group Wagner, which first deployed to the CAR in 2018.
Voters cast 95.27% of their ballots in favor and 4.73% against, with a turnout of 61.10% in the July 30 referendum, National Election Authority president Mathias Morouba said.
These "provisional" results must be ratified by the constitutional court, which is scheduled to publish the definitive outcome on August 27.
The new constitution would extend the presidential mandate from five to seven years and abolish the two-term limit.
There are no longer obstacles to prevent the 66-year-old head of state from seeking the presidency a third time in 2025. If elected, he could spend 16 years at the helm.
The vote was boycotted by the main opposition parties and civil society organizations, as well as by armed rebel groups.
The opposition complained about the lack of an up-to-date electoral register and said institutions tasked with guaranteeing a free and fair vote were not independent.
Government officials have cajoled and threatened referendum opponents, Human Rights Watch says, and authorities also banned an opposition rally in the capital in a bid to keep a lid on hostility to the poll.
"It's a comedy ... we've all seen that people didn't go out to vote and it doesn't reflect the will of the Central African people," said Crepin Mboli-Goumba, coordinator of the BRDC opposition coalition.
Touadera was first elected in 2016 as the country, with French and United Nations' help, emerged from a civil war that spiraled along sectarian lines following a coup.
In 2020 Touadera won a second five-year term, after a vote interrupted by several incursions by armed rebel groups. He also had to overcome allegations of fraud.
The Constitutional Court in September 2022 dealt a humiliating blow to Touadera, scrapping the establishment of a committee tasked with drafting the new constitution.
The court's president, Daniele Darlan, was then targeted in violent verbal attacks by Touadera supporters and in January this year was forcibly retired.
Since December 2020, hundreds of Wagner fighters and Rwandan troops have been deployed to face an offensive led by an alliance of the country's most powerful rebel groups, which have found themselves pushed into rural areas.