"The pipeline is shut down because there is a fault at one point of the line," the official told Dow Jones Newswires. He gave no details of the causes of the fault.
He said North Oil Co. technicians are repairing the fault but didn't know how long it would take.
Kirkuk crude oil stores at Ceyhan are very low, the official said.
Acts of sabotage against the northern export pipeline has rendered it idle for most of the time barring the last four months since the U.S.-led invasion of Iraq in March 2003.
Iraq's State Oil Marketing Organization has started selling Kirkuk crude oil to European and U.S. customers through term contracts from the beginning of 2008. Before that, the marketing company used to sell Kirkuk crude through competitive auctions whenever there is enough crude in Ceyhan for sales.