Former rebel chief Guillaume Soro on Thursday fired a verbal broadside at presidential elections in Ivory Coast next month after supporters of ex-head of state Laurent Gbagbo called for protests ahead of the vote.

Soro declared he would remain a candidate for the October 31 ballot despite being barred by a court, even as he lashed the poll as a scheme to enshrine 78-year-old Alassane Ouattara as president.

"My candidacy is firm, unchangeable and irrevocable," Soro, a former prime minister, told journalists in Paris.

He said his country had been driven to "the brink" by Ouattara's decision to seek a third term in office.

Anger: Former Ivory Coast president Laurent Gbagbo, left, and former rebel leader and ex-premier Guillaume Soro
Anger: Former Ivory Coast president Laurent Gbagbo, left, and former rebel leader and ex-premier Guillaume Soro POOL / MICHAEL KOOREN

Violent protests against Ouattara's candidacy left around 15 dead last month and demonstrations broke out in several cities this week including in Bonoua despite a ban on rallies.

Tensions in the West African state, a major producer of coffee and cacao, have revived traumatic memories of a months-long civil war that erupted after elections in 2010, claiming more than 3,000 lives.

Soro's help during that divisive conflict enabled Ouattara, who had claimed electoral victory over Gbagbo, to come to power.

He served as prime minister from 2007 to 2012 and then as speaker of parliament for seven years before falling out with the president and heading for France, the former colonial power.

Ouattara is bidding for a third term in office despite accusations that this sidesteps limits on presidential tenure
Ouattara is bidding for a third term in office despite accusations that this sidesteps limits on presidential tenure AFP / Ludovic MARIN

Soro said the October 31 poll "does not make any sense" as it was designed to "endorse the institutional state coup d'etat of Alassane Ouattara".

He urged the public to unite against Ouattara and for opposition leaders to press the regional bloc ECOWAS to secure "transparent elections."

Ivory Coast's top court, the Constitutional Council, has rejected 40 presidential election candidates, leaving only four.

It validated Ouattara's contested bid but sidelined Soro and Gbagbo on the grounds that they had been handed jail terms in absentia.

People walk past a billboard in Abidjan urging peaceful elections next month
People walk past a billboard in Abidjan urging peaceful elections next month AFP / SIA KAMBOU

Gbagbo supporters on Wednesday called for mass protests to "block... the dictatorship of Ouattara."

The appeal was made by a coalition called Together for Democracy and Sovereignty (EDS), which includes the Ivorian Popular Front party founded by Ggagbo and his influential wife Simone.

The government on Tuesday extended the ban on demonstrations, introduced in August, until September 30.

Ggagbo was freed conditionally by the International Criminal Court (ICC) in The Hague after he was cleared in January 2019 of crimes against humanity.

He is living in Brussels pending the outcome of an appeal against the ICC ruling.

Ouattara had said in March that he would not seek a third term but made a U-turn just four months later when his preferred successor, prime minister Amadou Gon Coulibaly, died of a heart attack.

The argument behind his bid rests on a change to the constitution in 2016.

Supporters say the modified charter has reset the two-term limits to zero, entitling Ouattara to run again.

On Tuesday the African Court, a pan-African tribunal on human rights, called on the Ivorian authorities to allow Soro to contest the vote.

Its ruling will have negligible impact, as Ivory Coast in April withdrew its recognition of the court's jurisdiction.