The fire broke out in a major crude oil tank on Wednesday night before spreading to a second refinery on a road southwest of Arbil, capital of the autonomous Kurdistan region, the civil defence agency said.

Thick plumes of black smoke and balls of orange flame rose into the sky above the facility, an AFP photographer reported.

The civil defence agency said the fire "started in one refinery before spreading to another".

"More than 10 people were injured, mainly men from the Arbil civil defence," it said in a statement, adding four fuel tanks and three fire trucks were burned.

Arbil governor Omed Khoshnaw said three rescuers were being treated in hospitals for burns and another 10 suffered breathing difficulties.

The main tank that was impacted contained over 5,000 tonnes of fuel, he said, putting the estimated cost of the damage caused at $8 million.

"So far, we don't know what caused it," said Khoshnaw, adding it could have been an electrical short circuit.

The fire still was still raging on Thursday afternoon despite the deployment of 30 rescue teams who were trying to prevent it from spreading further, the civil defence agency said.

With Iraq experiencing scorching summers, the country has seen multiple fires in recent weeks, affecting shopping centres, warehouses and hospitals.

Iraq is one of the world's biggest oil producers and crude oil sales make up 90 percent of Iraqi budget revenues.

But exports from the Kurdistan region have been halted for more than a year in a dispute over legal and technical issues.