In a quarterly report released today, UNAMI said the office of Prime Minister Nuri al-Maliki had complained in January that the UN mission's casualty reports were exaggerated. Al-Maliki has barred other Iraqi officials from releasing further data.
In its January report, UNAMI said more than 34,400 people had died in violence in Iraq during 2006.
Today's report defends those statistics, saying they are based on figures from Iraqi ministries.
The UN report also expressed concern about the treatment of thousands of suspects detained in a security crackdown in Baghdad during the past two months. It says the detainees have no guarantee of legal rights.
The UNAMI report warned that daily living conditions in Iraq are deteriorating, with a 60 percent unemployment rate and 54 percent of Iraqis living on the equivalent of less than one U.S. dollar a day.
Addressing Iraq's northern Kurdish provinces, UNAMI raised concerns about the high incidence of "honor killings" of women for "suspected 'immoral' conduct," citing some 40 cases this year.
It also said journalists in the Kurdish region face arrest and harassment for reporting on government corruption and other controversial issues.