The government intends to auction off oil contracts to foreign companies for the first time since Iraq nationalized its oil industry more than three decades ago.

The man behind the plan, Oil Minister Hussain al-Shahristani, appeared before parliament on Tuesday, where some lawmakers questioned the legality of the proposed contracts and what they called favorable terms for the foreign companies.

Iraq is thought to have one of the world's largest supplies of crude oil, with 115 billion barrels in proven reserves. But foreign know-how is key to its plans to boost oil output to four million barrels a day within four to five years, from 2.4 million barrels currently.

Despite security risks, Western oil companies are clamoring to get in. Iraq is still relatively unexplored, offering big companies a potentially easy-to-tap source of growth.

The six oil fields at stake are believed to hold reserves of more than 43 billion barrels.