The fire broke out in an asphalt tank on Wednesday night before spreading to a second refinery on a road southwest of Arbil, capital of the autonomous Kurdistan region.

Firefighters worked through the night battling to extinguish the flames, which sent thick plumes of black smoke and balls of orange flame into the sky, an AFP photographer reported.

"More than 10 people were injured, mainly men from the Arbil civil defence," the agency said in a statement, noting three fire trucks were burned.

The cause of the blaze was still unknown, it said.

"The fire started in one refinery before spreading to another," the statement said. Four fuel tanks had been affected.

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.