The Iraqi government opened up eight large oil and gas fields to international firms on Monday, paving the way for major investments by Western companies in one of the world's largest sources of petroleum.

That could be good news for consuming nations facing record oil prices near US$140 per barrel, and pushing producers to put more crude on the market. Iraq is one of the few countries in the world with vast oil and gas reserves that have not been fully developed.

But some fear that a major role for Western firms such as Shell, BP, Exxon Mobil and Total could feed allegations that United States-led forces toppled Saddam Hussein to grab the country's natural resources - a claim repeatedly denied by Washington.

During a press conference Monday, Oil Minister Hussain al-Shahristani named 35 companies that would qualify to bid on service contracts for eight oil and gas fields. The firms included seven from the US, three from Britain and others from countries like Russia and China.

Al-Shahristani said the companies would be invited to bid on the oil fields of Rumeila, Zubair, Qurna West, Maysan, Kirkuk and Bay Hassan; and the natural gas fields of Akkaz and Mansouriyah.

"These fields were chosen because their production can be raised in a short time and at a low cost," said al-Shahristani.