The premier received a boost with new results coming from the southern Shia provinces of Basra, Karbala and Dhi Qar.
Allawi led the prime minister with 9,000 votes on Tuesday. However, in the crucial province-by-province tally, al-Maliki has been ahead throughout the race, winning in seven out of Iraq's 18 provinces to Allawi's lead in five.
Advisers from the United Nations Assistance Mission for Iraq (Unami) have been monitoring the vote, updating election results on a special website built specifically for this year's elections.
The parliamentary elections, Iraq's second only for a full-term parliament since the 2003 US invasion, will determine who gets to form the next government that will rule as US troops leave.
Al-Maliki's State of Law:
Iyad Allawi's Iraqiya: 2,408,547
Iraqi National Alliance:
* 89.65% of national domestic votes have been counted so far
But the vote counting has been a long process, with results being portioned out piecemeal by election officials and almost immediately subject to fraud accusations.
In the all-important Baghdad, both al-Maliki and Allawi picked up about 20,000 new votes, the latest results showed, another indication of the narrowness of the race.
Parliament seats are apportioned mainly by how well coalitions do in the provinces, not according to overall vote.
Allawi's Sunni support is likely due to his nonsectarian stance and repeated condemnations of the influence of Iraq's powerful Shia neighbour, Iran.
With so much at stake, several leading candidates have raised accusations of fraud. Al-Maliki's bloc accused election officials of doctoring the vote counts and called for a re-count on Tuesday.
Qassim al-Aboudi of Iraq's electoral commission sought to assure all candidates of the fairness of the election process the following day.
Al-Aboudi said: "We reassure all the political entities that the electronic counting centre is rechecking all the results counts from all the provinces."