About 70 voting stations are to be set up in six large cities including Tehran, said poll organiser Kate Pryce.
Pryce told a news conference on Tuesday that registration was scheduled for 17 to 23 January and that the ballot would be from 28 to 30 January. "Each voter must present two identifications, one of which must carry a photo," she added.
The UN's International Organization for Migration is in charge of the polls for Iraqis living in 13 foreign countries.
However, the main Iraqi Shia party has criticised some of the registration procedures.
A top member of the influential Supreme Council of Islamic Revolution in Iraq (SCIRI) said of the 13 foreign countries where Iraqi exiles can vote, only those living in Iran "have to present an Iraqi ID card".
"In other countries it is enough to show an ID that simply indicates the person was born in Iraq," the head of SCIRI in Iraq, Abd al-Aziz Hakim, told the state news agency IRNA.
He also criticized the lack of polling stations in the cities of Isfahan, Shiraz, Yazd and the western province of Ilam, "where many Iraqis live".
"About 40,000 Iraqis live in Isfahan while no polls have been considered there." he added.
Hakim tops the Shia list in the 30 January elections.
Politically supported by Iran, SCIRI was created in early 1980s and is based in Iran.
Iranian President Muhammad Khatami said on Sunday that he was opposed to any postponement of Iraq elections, arguing that a delay could worsen the security situation there.
Khatami said he wanted to see "a government come to office and prepare the ground for the exit of occupation forces", as well as "cooperation between all regional and world countries to reconstruct Iraq."