Incumbent president Paul Biya is widely expected to be re-elected in the poll, contested by more than 20 rivals from the splintered opposition.
“Sunday’s poll was marred by massive fraud, numerous irregularities, conscience buying, and the very low turnout, among the many lapses,” said Jean Jacques Ekindi, presidential candidate for the minor Progressive Movement party, who has asked Cameroon’s Supreme Court to annul the whole vote.
A court official told Reuters he has received 12 lawsuits and was expecting more, many of alleging irregularities by the elections organiser ELECAM, which opposition parties say is controlled by the government.
International election observers have praised the peaceful conduct of the vote but raised concerns over the electoral process.
The Commonwealth observer mission, in its preliminary findings, said the use of state resources in Biya’s campaign “challenged the notion of a level playing field”.
Biya, 78, acknowledged there may have been “imperfections” in the staging of the election, but denied fraud.
Biya’s ruling CPDM party also filed a complaint asking the court to annul the result in an opposition stronghold in the country’s North-West region, officials said.
Vote tallying will begin on Friday but the results are not expected for another week.