The coalition of Iraq's incumbent prime minister, which came second in inconclusive March elections, has claimed up to 750,000 votes had been tainted by fraud and it is seeking a recount in five provinces.
The election had no clear winner, leaving Iraq facing months of negotiations on a new government and a power vacuum that insurgents have tried to exploit as US troops prepare to end combat operations.
Five months of political impasse after the last national vote in 2005 allowed sectarian bloodshed to take hold.
The all-out war between majority Shias and Sunnis who dominated Iraq under Saddam Hussein has faded, but Sunni Islamist insurgents continue a campaign of suicide bombings.
The State of Law alliance headed by Shia Prime Minister Nuri al-Maliki got 89 out of 325 parliamentary seats in the 7 March vote.
That was two seats behind the cross-sectarian Iraqiya alliance led by former Prime Minister Iyad Allawi, which won broad backing from the Sunni minority.
Mr Maliki said on 31 March his coalition had appealed against the results to the Independent High Electoral Commission.
At the time, he said any irregularities were unlikely to have a significant influence on the formation of the next government.
His alliance said today that it wanted a recount in five provinces, and at the very least votes should be tallied anew in Baghdad.
The capital is the most populous of Iraq's 18 provinces and counts for 68 seats, just over a fifth of parliament.
‘We believe the amount of manipulation in the votes in these five provinces could reach 750,000 votes ... this is a huge number and possibly could change enormously the election results,’ coalition spokesman Hachim al-Hasani told reporters.
‘This is why we presented this appeal and we hope that the judicial appeal panel will do its duty ... and look into it seriously.’
He said most of the votes affected by fraud would otherwise have gone to the State of Law coalition.
The US and the UN have said the Iraqi election appeared to be reasonably fair though not perfect.
