Nigeria's vice-president cannot run in April's polls, says The Independent National Electoral Commission (Inec).
Many see Atiku Abubakar as the ruling party's main challenger
Inec said candidates indicted for graft, including Atiku Abubakar, are not on the official list of candidates to be published on Thursday.
Mr Abubakar, standing as an opposition presidential candidate after falling out with the president, told the BBC he will challenge the decision in court.
Last week, an Abuja court ruled Inec has no power to disqualify candidates.
Inec spokesman Barrister Philip Umeadi told reporters that Mr Abubakar would only be allowed to run if he is cleared before the elections.
The vice-president is challenging the indictment in court.
His supporters say Nigeria is heading for anarchy if Inec does not stop flouting court orders.
The list of presidential candidates qualified to contest the forthcoming election will be published on Thursday.
Mr Abubakar was a former ally of President Olusegun Obasanjo, but fell out with the president after he publicly opposed moves to change the country's constitution to give the president a third term.
Mr Obasanjo's political loyalists then forced Mr Abubakar out of the ruling People's Democratic Party and he joined the opposition Action Congress on whose platform he is running for president.
Mr Abubakar, interrupted his campaigning to go to London at the weekend after damaging his knee.
He fell off his running machine and tore a tendon, according to his spokesman Garba Shehu.
On Sunday, ruling party candidate Umaru Yar'Adua returned to Nigeria from an emergency overseas health visit.