“Voting will continue tomorrow so that these people will have the opportunity to cast their ballots,” electoral commission spokesman Christian Owusu-Parry said on local radio.
Asked who he was referring to, he said those affected by biometric machine breakdowns.
Further details were not immediately available, though the electoral commission was expected to issue a statement.
Ghana has been seeking to live up to its reputation as an example of stable democracy in turbulent West Africa in the tight election.
Voting went smoothly in many areas, but the new biometric system requiring electronic fingerprints from voters suffered a number of breakdowns in certain districts. Materials also arrived late in some areas, causing some polling stations to open behind schedule.
President John Dramani Mahama is vying for a first elected term against main opposition candidate Nana Akufo-Addo in a nation reaping the benefits of a booming economy fuelled in part by a new and expanding oil industry. The results are expected to be close.