Ruling party candidate Bola Ahmed Tinubu is leading Nigeria’s most hotly contested general election since the country's return to democracy over two decades ago.
Fourteen of the 36 states have thus far been officially declared by the Independent National Electoral Commission (Inec).
Mr Tinubu has now secured 44% of the votes counted so far.
The main opposition candidate Atiku Abubakar is trailing in second, followed by Labour's Peter Obi.
In order to win the presidency, a candidate needs to have the most votes overall and win 25% in 25 of Nigeria’s 36 states.
But the electoral process has been mired in controversy.
Late on Monday, both of the main opposition parties walked out of the national collation centre in the capital, Abuja, where results were being announced.
They accused the electoral body of a lack of transparency around a new electronic voter system, a claim the commission denies.
European Union observers said the electoral body's poor planning and communication undermined trust in the process.
The polls have also seen major upsets. Mr Tinubu was defeated in Lagos, his stronghold for over two decades, by a surprise third party candidate Peter Obi who has galvanised support among Nigeria's youth.
Mr Abubakar, Mr Tinubu's main rival, won Katsina, the home state of outgoing President Muhammadu Buhari who is supporting Mr Tinubu.
Nigeria's new president will face a myriad of problems including worsening insecurity, rising unemployment and a failing economy