Guinea is set to vote on Sunday in a referendum on a new constitution that would permit junta leader Mamady Doumbouya to run for president, something he vowed not to do when he seized power four years ago.

Wednesday is the final day of campaigning for the referendum, the latest attempt at a political transition in West and Central Africa, where eight coups between 2020 and 2023 reshaped the regional political landscape.

A transition charter adopted after the September 2021 coup said junta members would be barred from standing in the next national and local elections, but the new constitution does not include that language.

Doumbouya has not said what his plans are. His critics have criticised the referendum as a power grab.

Exiled opposition leader Cellou Dalein Diallo on Monday urged Guineans to boycott what he called a "masquerade".

Diallo's Union of Democratic Forces party is currently suspended, along with ousted President Alpha Conde's Rally of the Guinean People, for failure to comply with administrative and financial disclosure requirements imposed by the junta. The parties have not been permitted to campaign against the new constitution.

Human Rights Watch has accused Doumbouya's government of disappearing political opponents and arbitrarily suspending media outlets. The government has denied any role in disappearances but has vowed to investigate such allegations.

The government missed a December 31, 2024 deadline it set for a return to a civilian administration. The presidential election is currently expected to take place in December.

The new constitution would lengthen the presidential term from five years to seven, renewable once, and create a Senate. The president would directly appoint one-third of senators, with two-thirds selected by municipal and regional councils.

More than 6.7-million voters are registered, and the new constitution would be adopted if more than 50% of those voting approve it.

Ibrahima Camara, a civil servant, has changed his social media avatars to a picture featuring the word "Yes", signalling his support.

"It's the most clear-sighted choice," he said. "We need a vote so Guinea can be governed by a constitution, a first step towards normalising the country."

But in opposition strongholds, scepticism runs deep.

"I won't vote because the process isn't transparent," said Abdoulaye Diallo, a resident of Hamdallaye, also in Conakry. "You can't talk about voting in Guinea without the main parties. In the long run, this will create unnecessary tensions."