The Iraqi government says it's opened six oil fields to international bidding as the nation tries to boost production.

Oil Minister Hussain al-Shahristani says 35 oil companies qualified for bidding, including several majors from the West, such as Shell, BP, Exxon Mobil and Total.

He says the oil fields are: Rumeila, Zubair, Qurna West, Maysan, Kirkuk and Bay Hassan.

All the fields are already producing oil, but al-Shahristani said Monday the new contracts would raise Iraq's production by 1.5 million barrels per day.

The deadline for the bids is the end of March 2009, and preliminary contracts will be signed next June.

Al-Shahristani says Iraq will also open natural gas fields of Akkaz and Mansouriyah for bidding. He gave no timeframe for that.