"There are 5.7 million primary school age children in Iraq, and we estimate that a minimum of 10 percent of those would need support," said Carel de Rooy.
He cited the case of an Iraqi colleague, whose 9-year-old son became hysterical and had to be sedated after a missile fell close to their home.
UNICEF has experience counseling children affected by other conflicts and natural disasters, including in East Timor, Mozambique and the aftermath of Hurricane Mitch in Central America.
The agency trains older children to work with younger ones in carefully controlled games designed to help them deal with what happened. The treatment costs about $20 per child.
De Rooy was evacuated from Iraq before the war started along with other non-Iraqi U.N. employees. The agency has 200 Iraqi staffers in the country, almost all in Baghdad.
Since leaving Iraq, de Rooy has been setting up aid operations in neighboring countries to prepare for an eventual return.
By Naomi Koppel