A UN report last week said malnutrition in under-fives had almost doubled since the US-led invasion of 2003.
The UK government says hunger levels fell between 2000 when a Unicef survey was carried out and 2004 when the Iraqi Statistical Office did its own survey.
The US ambassador to the UN in Geneva also criticised the UN findings.
Last week's report, by UN hunger specialist Jean Ziegler, blamed the worsening situation in Iraq on the war led by coalition forces.
About 8% of Iraqi children are now going hungry compared with 4% under former Iraqi leader Saddam Hussein, Mr Ziegler told the UN Human Rights Commission meeting in Geneva. ...
The UK's Department for International Development says the Unicef and Iraqi suggests a decline in child malnutrition from 17.3% in 2000 to 11.7% in 2004.