Yayi’s main rival, Adrien Houngbedji, claimed that more than a million potential votes were missing, although most other assessments put the figure much lower.
Benin was using an electronic voter list for the first time. The process occurred in several stages and required potential voters to provide electronic fingerprints and photographs.
"We are only at the beginning, my fellow citizens. There are surely errors," Yayi told journalists after voting in the economic capital Cotonou. "That's why, in the name of the country, I ask forgiveness from those who were omitted, if they exist."
A mop-up voter registration was originally to be held last Wednesday and Thursday to allow those left off to be signed up. It was extended through to Saturday when crowds mobbed sign-up centres and equipment broke down.