Iraq has invited international companies to build part of a new oil export pipeline linking the country's northern Kirkuk fields to Turkey, an oil ministry spokesman said on Monday.

The stretch of pipeline through Iraqi territory will act as a back-up to an existing pipeline that has suffered repeated bomb attacks and technical faults, said Oil Ministry spokesman Asim Jihad.

"We are keen to build a new pipeline as a backup," Jihad told Reuters. "A new export pipeline will provide flexibility to make oil flows continue if we have any issues with the old line," he added.

The pipeline may link to an existing route on the Turkish side, but several options are being considered, Jihad said.

Nine of the 15 international service companies invited to the tender have submitted bids, he said, without giving details. The winning bid is expected to be chosen in September, he added.

It is not clear whether the new pipeline will follow a similar route to the existing one which runs through the restive Nineveh province to Turkey's Ceyhan port on the Mediterranean.

The 900km existing pipeline has been bombed by militants about 30 times since the start of the year, disrupting oil flow, Jihad said.

It has a capacity of 1.6 million barrels per day (bpd) but normally carries only around 500,000 bpd due to repeated attacks and wear and tear during decades of wars and sanctions.

It is one of Iraq's largest crude oil export corridors but the nearly 40-year-old double line has also suffered regular maintenance and technical problems due to repeated leakages.

Kirkuk's exports sank to around 180,000 barrels a day last month versus 193,000 bpd in June. Apart from sabotage, northern exports are also lower due to the continued suspension of flows from Kurdistan. - Reuters