ABUJA (AFP) - Polling stations opened in Nigeria on Saturday, the electoral commission said, as voters went to the polls to elect a new president in what is being seen as the closest in the country's history.

"Polling stations have opened. Accreditation has started," Independent National Electoral Commission spokesman Kayode Idowu told AFP, despite reports of delays to the 8am (local time) start.

Reporters said the process had not started at some locations in Kano, Lagos and Abuja because of delays in the arrival of INEC officials and election materials. Voting proper is due to start at 1.30pm.