Ivory Coast's top court on Monday cleared the path for President Alassane Ouattara to seek a contentious third term, as protests turned violent in several cities and fears grew of a repeat of the conflict that claimed 3,000 lives in the West African country a decade ago.

The constitutional council also barred former President Laurent Gbagbo and former rebel leader-turned-Prime Minister Guillaume Soro from standing in next month's presidential election.

It cleared only four of the 44 candidates for the October 31 presidential election.

The other candidates cleared were former president Henri Konan Bedie from the historically dominant PDCI party, Gbagbo's former prime minister Pascal Affi N'Guessan, and Kouadio Konan Bertin, a dissident from Bedie's party.

In the economic capital Abidjan, protesters torched a bus in the working-class district of Yopougon after scuffles broke out earlier in the day between security forces and youths.

The district is thought to be a fiefdom of exiled former president Gbagbo, whose supporters had filed an application for him to run in the vote.

It was Gbagbo's refusal to concede defeat to Ouattara after the 2010 election that sparked the bloody conflict in the former French colony, formerly a beacon of stability and prosperity in the region.

In the centre-west city of Bangolo, demonstrators set fire to a mining truck and other vehicles on Monday, according to a resident, who added that gendarmes dispersed them with tear gas.

Witnesses said security forces took down barricades set up by protesters on several roads in the west of the country. 

About 15 people have died in violence since Ouattara, 78, announced last month that he would run for a third term.

The unrest has political observers worried that the vote could destabilise Ivory Coast, the world's top cocoa producer and French-speaking West Africa's largest economy.

Although the constitution limits presidents to two terms, Ouattara and his supporters argue that a 2016 constitutional tweak reset the clock.

The president had previously committed to not running again, but he changed his mind after the sudden death of his anointed successor - Prime Minister Amadou Gon Coulibaly - from a heart attack in July.

The electoral commission has said anyone convicted of a crime will be disqualified and has already barred Soro from running as he was sentenced in April to 20 years in prison for "concealment of embezzlement of public funds".

Gbagbo has been sentenced in absentia to a 20-year term for the looting of the local branch of the Central Bank of West African States during the 2010-11 crisis.

Former President Henri Konan Bedie is expected to be the opposition's main flagbearer, and his PDCI party nominated the 86-year-old as its candidate on Saturday.

At a rally attended by tens of thousands of supporters in the capital Yamoussoukro, Bedie pledged if elected to work for "the unconditional return of all exiles, as well as the release of all political, civilian and military prisoners from the post-election crisis".

Bedie is seeking to return to the presidency after he was removed in the country's first coup in 1999.