Opposition challenger Julius Maada Bio has been elected President of Sierra Leone after Wednesday’s presidential vote.

 Bio narrowly defeated the ruling All People's Congress candidate, Samura Kamara.

Chairman of the National Electoral Commission Mohamed Conteh announced that Bio  of the Sierra Leone People's Party (SLPP) won 51.81 percent of the ballots in the March 31 election compared with 48.19 percent for Kamara.

The official results of the vote had been delayed by a dispute over the method of tallying results that left ballot papers from 11,000 polling stations across the poor West African nation uncounted.

Just over 2.5 million people, or around 81 percent of eligible registered voters, cast their ballots in the presidential vote.

Bio, a former soldier who briefly led a military junta in 1996, is set to be sworn in as Sierra Leone's new president shortly following the announcement.

He replaces outgoing President Ernest Bai Koroma, who cannot seek re-election due to term limits.

This was Bio's second bid for the presidency, having lost in 2012.