Mr Allawi needs a simple majority of the 329 MPs in the vote as long as quorum is met to pass his government, according to the Iraqi Supreme Court.
The country is facing a domestic crisis. More than 500 people have been killed since early October in anti-government protests calling for an overhaul of the political system.
Mr Allawi said in a televised speech that if his government wins a confidence vote, its first act would be to investigate the killing of protesters and bring the perpetrators to justice.
He also pledged to hold an early election free from “the influence of money, weapons, and foreign interference” and called on protesters to give his government a chance.
Mr Allawi had a month-long deadline to form the new government, which he is expected to lead until early elections.
But his chances are 50-50 at the current time, as there is still some opposition to him from Sunni, Kurdish and even Shiite parties, Sajad Jiyad, a Baghdad based political analyst, told The National.
“Their major complaints are that he did not work with them to choose cabinet nominees and that his nominees are not acceptable candidates for Iraqis protesting against the political establishment,” Mr Jiyad said.
If Parliament does not pass Mr Allawi’s proposed government then parliamentarians would hold a second vote or President Barham Salih would select his own nominee, the analyst said.
“Both situations would be unprecedented, as indeed the current crisis is too,” Mr Jiyad said.
For Sunni and Kurdish parties, the opposition is not to Mr Allawi personally but to his refusal to accept their party nominees to hold ministries, Kirk Sowell, an Iraq expert at Utica Risk Services, said on Twitter.
“This is viewed as the reason for the failure of previous governments,” Mr Sowell said.
Kurdish and Sunni parties have said they fear the next Cabinet will not represent them.
Mr Allawi’s government will pass if he can get the support of the main Kurdish parties.
“He has enough votes from other parties to pass with their support. Without it, he doesn't,” Mr Sowell said.
Earlier on Thursday, local reports said that Mr Allawi sent a letter to the British embassy requesting the cancellation of his British citizenship.
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