The New Patriotic Party rejected President John Mahama's victory in the Dec. 7 election, alleging fraud, the BBC reported. Mahama, of the National Democratic Congress party, won the election with 50.7 percent of the vote over NPP candidate Nana Akufo-Addo, who took 47.7 percent.
The NPP said it waited to file the petition until it analyzed the results from Ghana's 26,000 polling stations. The party said it found irregularities in voting, including an extra 1.34 million votes cast.
Without those votes, Akufo-Addo would have won the election, the NPP said.
"We are ready to concede that in an election that involves more than 11 million voters there might be mistakes," Akufo-Addo said after the petition was filed at Supreme Court in Accra. "But why are the arithmetic mistakes so very often in favor of the NDC presidential candidate, John Dramani Mahama?
Akufo-Addo said the court challenge is intended to "deepen our democracy by strengthening the institutions that are mandated by our constitution to superintend the electoral process."
Johnson Asiedu Nketia, the NDC's secretary-general, said the ruling party did not believe the Supreme Court would rule against it, as the election was the country's most transparent ever.
"We don't have any shred of doubt in our minds that President Mahama has been the choice," Asiedu Nketia said.