The Nigerian president's declaration of a public holiday has delayed a supreme court hearing into whether the vice-president may stand in next week's election.
Garbu Shehu, Abubakar's spokesman, said the holiday was a "pre-emptive strike to subvert the sitting of the [supreme] court", which had been expected to start hearing the case on his exclusion from the list of candidates on Thursday.
The government said the holiday was declared to allow increased public participation in the elections.
"President Olusegun Obasanjo has declared Thursday and Friday as work-free days to enable people to travel in order to participate in gubernatorial and state house of assembly elections," a statement said.
Fraud allegations
Nigerians vote for state governors and legislators on Saturday. Voting for the president and national assembly is due a week later.
Dozens of mostly opposition candidates have been excluded from participating after receiving fraud indictments.
Abubakar, who was picked as presidential candidate for the Action Congress party, is among those charged.
The supreme court had been expected to hear evidence on Thursday in Abubakar's appeal against a lower court ruling that empowered the electoral body to exclude candidates.
The public holiday means that any outstanding cases relating to the governorship elections on April 14 are now redundant.
The holiday gives even less time to the supreme court to rule on Abubakar's case.
With Abubakar's candidacy still in doubt, the presidential vote is turning into a straight contest between Umaru Yar'Adua, standing for the ruling People's Democratic Party, and Muhammadu Buhari, standing for the opposition All Nigeria People's Party.