In a statement read at UN headquarters on Saturday, the world body's secretary general, Kofi Annan, said the team had arrived in the Iraqi capital.
"I am very pleased to announce that my fact-finding team has arrived and is about to begin intensive consultations with Iraqi leaders and the [Coalition Provisional Authority]," Annan said.
"The team will endeavour to meet representatives of all constituencies and listen to all Iraqi views and perspectives, without excluding any," said Annan. "I hope the work of this team will help resolve the impasse over the transitional political process leading to the establishment of a provisional government for Iraq."
Annan ordered the mission after US occupation forces failed to broker a compromise deal with the revered spiritual leader of the country's Shia majority, Grand Ayat Allah Ali al-Sistani, over its timetable for handing over power to the transitional government by 30 June.
"I hope this team will help resolve the impasse over the transitional political process leading to the establishment of a provisional government for Iraq."
UN Secretary General
Sistani is demanding direct elections for the transitional government, rather than the provincial caucuses envisioned by the US-led coalition.
French news agency AFP has reported the team comprises a dozen experts and the visit could last for 10 days.
The team, shielded by rigorous security, is the first official UN mission to the country since 22 people were killed in an explosion at the UN's Baghdad offices last year. Annan pulled foreign staff out of Iraq after the deaths.
"I firmly believe that the most sustainable way forward is one that comes from the Iraqis themselves," he said.
"Consensus among all Iraqi constituencies is the best guarantee of a legitimate and credible transitional governance arrangement for Iraq.
"I encourage efforts by the people of Iraq to form an Iraqi government based on the rule of law that affords equal rights and justice to all Iraqi citizens without regard to ethnicity, religion or gender."
US forces shot dead two Iraqis in
separate incidents on Friday
Meanwhile, violence continued between occupying forces and Iraqi fighters.
One Iraqi man died from wounds sustained when US soldiers opened fire on him and two others in the town of Samarra, the US military said.
Also on Friday, a US helicopter patrol shot dead an Iraqi after spotting smoke trails near Balad, 75km north of Baghdad, after a rocket attack on a US military base.
In the first instance, soldiers were investigating a possible homemade bomb on the side of the road when three Iraqis in a truck opened fire at 11:00 (0800 GMT) in Samarra, 125km north of Baghdad, a US spokeswoman said.
Troops returned fire, seriously wounding one man in the head.
He was treated by US medics at the scene before being taken to a local hospital by Iraqi police, said the spokeswoman for the 4th Infantry Division which patrols the area. The man died on Saturday.
In the Balad case, soldiers found a second attacker wounded in the bushes. Three discarded rocket tubes, one with a rocket still inside, were found nearby.
The attack on the base caused no damage and no casualties, the spokeswoman said.