An Italian member of Iraq's US-led Coalition Provisional Authority has resigned in protest at its policies.
Italy is preparing to bury its dead
Marco Calamai said few reconstruction projects had been implemented and warned that Iraqis were becoming angry.
Mr Calamai also told Italian newspapers the United Nations had to intervene in the country to improve a situation he described as "seriously compromised".
The criticism comes as Italy prepares to bury the 19 Italians killed in last week's bomb attack in Iraq.
Mr Calamai told Italian newspaper La Stampa the attack, in the southern Iraqi city of Nasiriya, was the consequence of "a mistaken policy and an under-evaluation of the complexity of the social structure of Iraq".
He also warned that the US needed to make radical changes to the policies it had adopted so far in the country.
An official state funeral is due to be held on Tuesday - which has been declared a national day of mourning - for those killed in the bombing.
The bodies are lying in state in Rome's Victor Emmanuel monument, dedicated to the Unknown Soldier.
Prime Minister Silvio Berlusconi, President Carlo Azeglio Ciampi and the Italian cabinet were among those who have paid their respects.
Worst single loss
On Monday crowds gathered in Rome to file past the coffins of the dead, all draped in the Italian flag.
"I am a mother who has a son in the carabinieri. I felt a really strong desire to be here. They are all my sons," said one woman, Antonella Regnon.
The last body - that of Corporal Pietro Petrucci - was returned to Italy after his parents gave permission for his life support machine to be switched off on Saturday.
His coffin was being brought to the monument to join the others.
The attack was the worst single bomb attack on international peacekeepers in Iraq, and the worst Italian military loss since World War II.
The Italian losses included 12 carabinieri, five army soldiers and two civilians. Nine Iraqis also died in the attack.