Oil exports from Iraq's autonomous Kurdistan region via the federal government have been slashed in the latest chapter of a long-running payments row, a spokesman said on Wednesday.

Kurdistan government spokesman Safin Dizai told AFP that foreign companies working in the region stopped their exports over 350 billion Iraqi dinars (about $291.6 million) he said they were owed by the federal government.

"We sent a letter to the government and we asked the government to pay, but they are refusing to pay," Dizai said.

Exports of less than 5,000 barrels per day (bpd) are nonetheless still ongoing, he said -- significantly down from over 100,000 bpd in past months.

"The companies will resume exporting oil when the government pays," Dizai said.

Kurdistan halted oil exports to the federal government on April 1 over $1.5 billion it said was owed to foreign oil companies in the region that Baghdad allegedly withheld, but announced in early August that they would be restarted.

The region reached a deal with Baghdad in mid-September under which it would export 140,000 bpd for the rest of that month and 200,000 bpd for the remainder of the year, and would meanwhile receive an "advance" of one trillion Iraqi dinars (about $833 million).

Faisal Abdullah, spokesman for Hussein al-Shahristani, Iraq's deputy prime minister for energy affairs, told AFP that the federal government had paid Kurdistan 650 billion dinars (about $541.6 million), and was awaiting records on payments to companies in the region to pay the remaining 350 billion dinars.

Kurdistan is meanwhile insisting the money be paid before providing the records, Abdullah said.

Baghdad and Arbil are at odds over issues including Kurdistan's refusal to seek approval from the central government for oil contracts it has awarded to foreign firms, and over a swathe of disputed territory in northern Iraq.

Baghdad says all oil deals must go through the national oil ministry and regards any that do not as illegal.