Chinese companies won four bids to explore Iraqi oil and gas fields, Iraq's oil minister said on Sunday as the Middle Eastern country's hydrocarbon exploration licensing round continued into its second day.

The oil and gas licences for 29 projects are mainly aimed at ramping up output for domestic use, with more than 20 companies pre-qualifying, including European, Chinese, Arab and Iraqi groups.

Chinese companies have been the only foreign players to win bids, taking nine oil and gas fields since Saturday, while Iraqi Kurdish company KAR Group took two.

There were notably no U.S. oil majors involved, even after Iraqi Prime Minister Mohammed Shia met representatives of U.S. companies on an official visit to the United States last month.

China's CNOOC Iraq won a bid to develop Iraq's Block 7 for oil exploration that extends across the country's central and southern provinces of Diwaniya, Babil, Najaf, Wasit and Muthanna, said oil minister Hayan Abdul Ghani.

ZhenHua, Anton Oilfield Services and Sinopec won bids to develop the Abu Khaymah oilfield in Muthanna, the Dhufriya field in Wasit and the Summer field in Muthanna respectively, the minister said.

Iraq's main goal with its sixth licensing round was to increase gas output that it wants to use to fire power plants that rely heavily on gas imported from Iran.

However, no bids were made on at least two fields with large gas potential, potentially undermining those efforts.

Iraq, OPEC's second-largest oil producer behind Saudi Arabia, has been hampered in its oil sector development by contract terms viewed as unfavourable by many major oil companies as well as recurring military conflict and growing investor focus on environmental, social and governance criteria.

(Reporting by Moayed Kenany Writing by Adam Makary and Timour Azhari Editing by David Goodman)