Iraqi Oil Minister Hussein al-Shahristani addresses the media during a break of the International Energy Forum in Rome (File)

The Iraqi government says it has opened six oil fields to international bidding, in an effort to boost the nation's oil output.

Iraq's oil minister, Hussein al-Shahristani, Monday announced 35 companies that would be qualified to bid on developing the fields of Rumeila, Zubair, Qurna West, Bai Hassan, Kirkuk and Maysan. The foreign firms include the major Western oil companies of Shell, ExxonMobil, Chevron, BP and Total.

Shahristani says the new contracts will raise Iraq's oil production by 1.5 million barrels a day.

Iraq currently produces 2.5 million barrels of oil per day and hopes to raise that to 4.5 million in the next five years.

The country's oil ministry announced last week that it also will sign short-term oil service contracts during the next month.

Shell, ExxonMobil, Total and BP, or their predecessors, had been partners in the original Iraq Petroleum Company, dating back to the 1920s. They had stopped operating in Iraq in 1972, when the country's oil industry was nationalized.

Some information for this report was provided by AFP, and Reuters.