Opposition presidential challenger John Atta Mills has won Ghana's presidency at his third attempt, returning the National Democratic Congress (NDC) founded by former President Jerry Rawlings to power after eight years out of office.

The chairman of the Electoral Commission of Ghana, Kwadwo Afari-Gyan, announced in Accra on Saturday that Atta Mills had won 50.23 percent of the vote, while Nana Akufo-Addo of the National Patriotic Party (NPP) won 49.77 percent.

The African Elections Project (AEP) reports from Accra that the commission's certified results showed that the NDC won 4,521,032 votes and the NPP 4,480,446 votes. The commission said 72.91 percent of the country's 12,472,758 voters had cast ballots.

Atta Mills previously lost two elections to the now outgoing President John Kufuor - first in 2000, when Rawlings' term of office came to an end, and again in 2004.

His election marks the second successive victory of an opposition candidate at the end of an outgoing president's term of office.

Saturday's announcement of the final election result followed an election in the remote western constituency of Tain on Friday. The vote in Tain was delayed by problems with ballot papers and Atta Mills' lead was so narrow that the electoral commission judged that the outcome in Tain had the potential to overturn it.

Atta Mills won Tain comfortably after the NPP boycotted the polls. The NDC had won the constituency in parliamentary voting on December 7.

Earlier in the week both the NPP and NDC made allegations of electoral irregularities, in the Volta and Ashanti regions respectively. The electoral commission said on Saturday that neither party had been able to provide sufficient evidence to invalidate the result.