Iraqi oil exports rose for a second consecutive month in May, figures showed Sunday, despite a northern pipeline remaining disabled and a central government row with the country's Kurdish region.

Crude exports averaged around 2.58 million barrels per day (bpd) last month, all of which were shipped from Iraq's southern export terminals, the oil ministry said in a statement.

The sales raised $8.68 billion in revenues.

The average daily exports marked an increase from April's figure of 2.50 million bpd, but fell short of February's multi-decade high of 2.80 million bpd.

Exports in Iraq have been hit by persistent militant attacks on a pipeline connecting the northern province of Kirkuk to the Turkish Mediterranean port of Ceyhan.

The pipeline has been disabled since early March, and it is not expected to be up and running for several days.

At its peak, it was carrying upwards of 500,000 bpd to international markets via Turkey.

Exports have also been limited by a row between the central government and the autonomous northern Kurdish region.

Iraqi Kurdistan shipped oil to international markets via Turkey last month, sparking a furious response from Baghdad, which insists such shipments without the expressed consent of the central government constitute smuggling.

Iraq has filed an arbitration case against Turkey at the Paris-based International Criminal Court and has threatened legal action against any companies which buy the oil.

Iraq's draft 2014 budget calls for the Kurdish region to export around 400,000 bpd.

Oil revenues account for the lion's share of government income, and the authorities are seeking to dramatically ramp them up to fund much-needed reconstruction of Iraq's conflict-battered economy and infrastructure.