An influential faction in Nigeria's main opposition party said on Wednesday it had pulled out of the campaign council for the party's presidential candidate Atiku Abubakar, which could weaken the party's chances at the February election.

Political parties in Nigeria will officially start campaigning next week for the election to pick a successor to President Muhammadu Buhari, who steps down after serving a final four-year term.

Abubakar, presidential flag bearer for the People's Democratic Party (PDP), Bola Tinubu of the ruling All Progressives Congress party and Peter Obi of the Labour Party are the main contenders in a field of 18 candidates.

But the PDP faces internal strife over the position of its chairperson, which culminated in Wednesday's decision by a faction of the party to pull out of Abubakar's campaign.

The camp, led by Nyesom Wike, an influential governor from oil-producing Rivers state, wants party chairman and Abubakar ally Iyorchia Ayu to resign and his position be taken by a candidate from southern Nigeria.

"Consequently, we resolve not to participate in the campaign council in whatever capacity until the resignation of Dr. Iyorchia Ayu," PDP stalwart Bode George, who spoke for the faction, told reporters after a meeting at Wike's residence in Port Harcourt.

Abubakar and Ayu are from northern Nigeria while Wike and most of his camp are southerners.

Charles Aniagwu, spokesperson for Atiku's campaign, could not be reached for comment.

In Nigeria, political power rotates between the largely Muslim north and mainly Christian south.

The PDP is seeking to return to power after it was swept from office by Buhari's All Progressives Congress party at the 2015 polls, the first time a sitting government was removed from office at the ballot box since the end of military rule in 1999.