Ivory Coast's President Alassane Ouattara, who is running for a contested third term in an election on Saturday, accused the opposition of sending supporters to their deaths by carrying out a campaign of civil disobedience.

Around 30 people have been killed in pre-election clashes since August, reviving fears Ivory Coast could slide back into the kind of violence that left 3,000 dead in a 2010-2011 crisis.

"They have to stop sending young people to their deaths. I don't see why the opposition calls for civil disobedience, which leads to criminal acts," Ouattara told AFP in an interview on Wednesday.

"We know the opposition has been creating problems. We have proof and after the elections we will start proceedings over this. We will prosecute the actors and the sponsors... whatever the rank of the person."

The campaign for the October 31 election has been marred by tensions as Ouattara, 78, faces off against two main opponents, former president Henri Konan Bedie and former prime minister Pascal Affi N'Guessan.

The opposition camp has called for civil disobedience and an "active boycott" of the vote, though they have still not withdrawn their candidacies.

Elected in 2010 and re-elected in 2015, Ouattara announced in March that he would reject a third term in office, before changing his mind in August after the sudden death of his designated successor, Prime Minister Amadou Gon Coulibaly.

Ivorian law sets a two-term limit for presidents but a constitutional council has ruled a reform in 2016 allows Ouattara to reset the clock and run again. The opposition rejects Ouattara's bid as unconstitutional.

Dozens of would-be candidates have been barred from running in the election, including Laurent Gbagbo and ex-rebel chief Guillaume Soro, who both played key roles in the 2010-11 crisis