(AFP) - Polls opened in a Chad on Sunday for a referendum on a new constitution, a vote seen as a key step toward elections and the return of civilian rule promised, but postponed, by the ruling military junta.

A large section of the opposition and civil society in the central African country have called for a boycott.

They say the vote is designed to pave the way for the election of the current transitional president, General Mahamat Idriss Deby Itno, and the continuation of a "dynasty" begun by his late father 33 years ago following a coup.

The "yes" camp seems assured of victory after a well-financed campaign by the ruling junta against a divided opposition, whose members have faced arrest, intimidation and threats for more than a year.

The capital N'Djamena has been plastered with posters championing a "yes" vote to bring in a constitution for a "unitary and decentralised state".

It is not very different from the constitution that the military repealed in 2021, enshrining a regime in which most of the power is concentrated in the head of state.

The "yes" camp says a unitary state is the only way to preserve unity, while federalism, sought by opposition groups, would encourage "separatism" and "chaos".

Deby was first to place his vote at a polling station in N'Djamena near the presidential palace.

"Each ballot placed in the ballot box is a further step towards stability and prosperity for our country," he said.

Polls will close at 5:00 pm (1600 GMT).

Provisional results are scheduled to be published on December 24, with the Supreme Court due to validate them four days later.

- 'Voting makes no difference' -

Voter turnout at midday in the capital appeared limited, according to AFP journalists.

The head of the body organising the referendum, Limane Mahamat, said that Sunday was a day of worship, suggesting that more people would head to polling stations later in the day.

But some electors in the capital remained defiant.

"Voting or not voting makes no difference, the result is known in advance," said Mahamat Issa, a civil servant who refused to cast a ballot.

In southern parts of the city, often opposition strongholds, AFP journalists observed a relative enthusiasm for the vote.

"I'm going to vote 'no' to respect the instructions of my party," said Gilbert Alain, adding that he was a "federalist".

In the north of N'Djamena, Zenana Mahamat was one of the few people out to vote at midday.

"I voted 'yes' for peace," she told AFP.

- 'Deby dynasty' -

The two main groupings of parties and civil society organisations hostile to the junta hope a low turnout will discredit a leader they accuse of perpetuating a 33-year "Deby dynasty".

The referendum is "purely and simply legitimising the dynasty that they want to impose on us," said Max Loalngar, coordinator of one of the groups, Wakit Tamma, who spoke to AFP by telephone from exile.

Deby, 37, was proclaimed transitional president by the army in April 2021 after the death of his father Idriss Deby Itno, who was killed by rebels on his way to the front line.

Deby senior had ruled Chad, the second-least-developed country in the world according to the United Nations, with an iron fist for more than 30 years.

His son promised elections after a transition period of 18 months, but his regime later extended the transition by two years and authorised him to run in a presidential election now scheduled for late 2024.

- Opposition repressed -

On October 20, 2022, between 100 and 300 young men and teenagers were shot dead in N'Djamena by police and military, according to the opposition and national and international NGOs.

They had been peacefully demonstrating against the two-year extension of the transitional government.

More than 1,000 others were imprisoned before being pardoned, while dozens more were tortured or have disappeared, according to NGOs and the opposition.

Most were supporters of prominent opposition figure Succes Masra, a longtime opponent of the Deby dynasty.

Yet in late October, Masra signed a reconciliation agreement with the regime and has been encouraging his followers to vote "yes" on Sunday.

© Agence France-Presse