Jihadists from the Islamic State group seized swathes of territory in oil-rich Iraq and neighbouring Syria in an offensive, and a US-led coalition has been launching strikes against the group.
The IMF said in its October World Economic Outlook that Iraq's gross domestic product is forecast to shrink by 2.7 per cent this year, down from the 5.9 per cent growth it forecast in April.
The fighting has prevented Baghdad from exporting oil to Turkey via pipeline and to Jordan by road.
"The conflict in northern Iraq has started to affect non-oil growth in that country," the IMF said.
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"Although most oil production is in the country's south and oil output levels have not been materially affected, the departure of skilled personnel will limit Iraq's ability to expand or, possibly, even maintain oil production," the IMF said in the report.
Iraq, which pumps around 3.5 million barrels per day, is OPEC's second largest exporter after Saudi Arabia.
So far, oil prices have remained unaffected by the geopolitical tensions in the Middle East due to a weak global demand and a hike in US production. Brent crude dropped from around USD 110 (87 euros) a barrel to USD 93 a barrel.