A European diplomat said on Thursday the world body team will stay in Iraq for about 10 days.
He did not specify how many members will make up the team, but said it will be led by Uruguay's Carina Perelli. She is the chief of the electoral assistance division at the UN headquarters in New York.
Perelli visited Iraq last summer, before the 19 August attack that destroyed the UN offices in Baghdad and killed 22 people, including top UN envoy to the country, Brazilian diplomat Sergio Vieira de Mello, forcing the world body to pull its staff out.
UN Secretary General Kofi Annan gave the green light for the trip after Washington called for the UN to intervene in a potential crisis with Iraq's top Shia spiritual leader Grand Ayat Allah Ali al-Sistani.
Al-Sistani opposes a US plan to select a transitional assembly through a regional caucus system ahead of a 1 July deadline for transfer of power from the US-led occupation to an Iraqi authority.
The cleric has been insisting on direct elections, but Washington maintains that nationwide elections in Iraq are not possible and has so far refused to budge on the handover date.
On Wednesday, Annan said the deadline might have to be reconsidered to forge an agreement on a provisional government. But Washington reiterated on Thursday it will not allow early elections to go ahead with the ongoing anti-occupation attacks.
Meanwhile, a little-known Iraqi group has claimed responsibility for the twin blasts in the northern Iraqi city of Arbil. The toll from Sunday's bombings climbed to 109 on Thursday with more than 200 injuries.
Iraqi Shia have taken to the
streets in support of al-Sistani
In a statement posted on a website, the so-called Jaish Ansar al-Sunna claimed responsibility for Sunday's blasts at the offices of the two main Kurdish parties.
On Wednesday it said it targeted the "dens of the devils" because of the parties' support of the United States. The claim could not be independently confirmed. The site which carried the statement has frequently carried past claims for attacks.
The attacks killed numerous officials of the Kurdistan Democratic Party (KDP) and the Patriotic Union of Kurdistan (PUK). They are among the strongest allies of the United States in the country and fought alongside its troops during the war against Iraq last March.
The name of the organisation was included among a dozen groups that issued a joint statement this week in Ramadi and Falluja-hotbeds of anti-occupation attacks-warning Iraqis against cooperating with the US-led occupation.
Jaish Ansar al-Sunna is believed to be an off-shoot of Ansar al-Islam, which operated in northern Iraq. During the first weeks of the US-British war, Peshmerga or Kurdish fighters wiped out some of their bases.
The organisation, included on Washington's list of "terrorist" groups, was comprised of a few hundred fighters. It has apparently produced a CD including the testimonies of fighters encouraging attacks on occupation and affiliated targets.