Ghana's Supreme Court is due to rule on an opposition petition to annul President John Mahama's narrow victory in last year's disputed election.

The NPP alleges that Mr Mahama won the election fraudulently, a charge his NDC party denies.

The case has been broadcast live on television and radio in a rare case of judicial transparency in Africa, says the BBC's Akwasi Sarpong in Accra.

Ghana is generally seen as a beacon of democracy in the region.

'Spellbound' Nearly 30,000 security officers have been deployed across Ghana to prevent an outbreak of violence when the court gives its ruling.

Mr Mahama, from the National Democratic Congress (NDC), won the December 2012 election with 50.7% of the vote, compared to the 47.7% of his rival, Nana Akufo-Addo of the New Patriotic Party (NPP).

The election went off peacefully, and both Mr Mahama and Akufo-Addo have pledged to respect the court's decision.

Mr Mahama was inaugurated in January.

Ghanaians have been spellbound by the eight-month case, following it closely on radio and television, our reporter says.

Court cases are not usually beamed into the homes of people, he says.

The NPP has asked the court to scrap some four million votes, alleging the result was tampered with to guarantee Mr Mahama victory in the first round of the election.

The NDC argues that any mistakes made by polling station officials while recording ballots was not an attempt to subvert democracy, and there are insufficient grounds for the court to overturn the result.