The country's crude oil output could grow to 6.1 million barrels per day (mbpd) in eight years' time from about 3.0 mbpd currently, the IEA said as it unveiled its Iraq Energy Outlook report in London.

The Paris-based IEA added that Iraq stood to gain almost $5.0 trillion (3.85 trillion euros) in revenue from exporting oil up to 2035, as long as the country invested more than $530 billion on raising its energy output.

"In our central scenario, Iraq's oil production more than doubles to 6.1 mbpd by 2020 and reaches 8.3 mbpd in 2035," said the IEA, which advises oil-consuming developed countries on energy policy.

"The largest increase in production comes from the concentration of super-giant fields in the south around Basra," it added.

But reaching such a high level of output "will require rapid, co-ordinated progress all along the energy supply chain," the agency stressed.

"Adequate rigs will need to be available at the right time. Early investment in a challenging project to bring up to eight mbpd of water inland from the Gulf to Iraq's southern fields will be essential to support oil production and to reduce potential stress on scarce freshwater resources."

Iraq has proven reserves of 143.1 billion barrels of oil and 3.2 trillion cubic metres (111.9 trillion cubic feet) of gas, both of which are among the largest in the world.

Baghdad is looking to dramatically ramp up both production and sales in the coming years, bringing in much-needed cash to rebuild its conflict-battered economy.