Iraq aims to ramp up oil production by nearly 45 percent by the end of next year - without any input from autonomous Kurdistan region - which suggests a lasting compromise in their long-running oil feud may be a way off.

Baghdad's ambitious 4.5 million barrels per day (bpd) target specifically excludes output from the northern Kurdish region, senior Iraqi officials said, and relies on new oil pumped from southern oilfields and higher flows from ones already producing.

Thamir Ghadhban, energy adviser to Iraq's prime minister, said Baghdad had lost confidence in Kurdistan Regional Government (KRG) after it stopped exporting oil through the federal pipeline system.

"The 4.5 million barrels a day is based on the development of the resources within the 15 governorates excluding Kurdistan because of this issue," Ghadhban, a former oil minister of Iraq, said at an energy conference in London on June 18.

KRG says it is owed more than 4 trillion Iraqi dinars, or $3.5 billion, by Baghdad to cover the costs accumulated by oil companies operating there, while the central government rejects those contracts as illegal.