Former military ruler Muhammadu Buhari claims he has beaten Christian incumbent President Goodluck Jonathan.
The retired general's spokesman said: "As for the election, we have won it".
A number of states have still to declare their votes but it is becoming increasingly difficult for Mr Jonathan to win.
Mr Buhari's spokesman added: "We are not out of the woods yet, we don't know what tricks the government are going to play."
If the result is confirmed it would be the first time an incumbent president has lost an election.
Speaking to Premier on Monday Revd Canon Hasan John from the Diocese of Jos said the best outcome for Christians was a victory for Goodluck Jonathan.
He said: "This is simply because when Buhari was in the army a lot of Christians believe that he has been instrumental to the imposition of Sharia law in some of the northern states.
"He's not apologetic about it. During his tenure as a military dictator he has issued a number of decrees that are anti-Christian so a lot of Christians are just not comfortable with Buhari being the president."
A Nigerian Pastor and supporter of Buhari, Itua Ighodalo, spoke to Marcus Jones on Premier's News Hour. Listen to a cut of the interview here: