The Shuaiba refinery's capacity should increase to 280,000 bpd by the end of the year, as a result of the expansion, the statement said.
Iraq, OPEC's second largest oil producer, wants to build new refineries as its oil processing capacity was severely curtailed by damage to its largest plant in Baiji, north of Baghdad, when it was captured by Islamic State militants in 2014.
Baiji was retaken by Iraqi forces in 2015 and it should be brought back on line partially this year. Iraq now relies on the Doura refinery, in Baghdad, and Shuaiba.