Iraq's election commission has ordered a manual recount of votes cast in Baghdad province, after complaints from Prime Minister Nouri Maliki, BBC reported.
The recount, ordered by a judicial panel, covers more than 2.5m ballots which account for 68 seats in the 325-seat Council of Representatives.
Although Mr Maliki's State of Law coalition came first in Baghdad with 26 seats, he had demanded a recount.
March's vote was narrowly won by the Iraqiya list of former PM Iyad Allawi.
Electoral commissioner Hamdiya al-Husseini said the manual recount would begin immediately, but she was not sure how long it would take.
Mr Maliki had alleged that the electronic system of vote counting was unreliable.
Mr Allawi's group won 91 seats, two more than Mr Maliki's State of Law coalition, sparking weeks of negotiations between parties to form a coalition government.
The leader of the group with the biggest number of seats will be asked to form a government.
But the negotiations to form a working majority for a coalition will be further delayed by this decision, the BBC's Jim Muir in Baghdad says.