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BEIJING, Dec 9 (Reuters) - China announced on Monday the establishment of a national oil and gas pipeline company in a move intended to boost competition, the Xinhua state news agency said.

The long-awaited state pipeline company aims to provide other investors fair market access to infrastructure that is mainly controlled by China's three national oil companies, Xinhua said.

"The new company will separate (oil and gas) transportation, production and sales, and open (transportation) to third-party entities, which will benefit market competition," said Xinhua, citing an unidentified official at the newly launched pipeline company.

The new entity is expected to manage most of the country's pipeline infrastructure, controlled by energy giants China National Petroleum Corp (CNPC), Sinopec and CNOOC, and some underground natural gas storage, as well as a few liquefied natural gas terminals.

As of end-2018, CNPC owned 63% of China's mainstream oil and gas pipelines, while Sinopec and CNOOC controlled 31% and 6%, respectively.

In a separate report on Monday, Xinhua said the new entity is expected be overseen by the State-owned Assets Supervision and Administration Commission (SASAC), which will have a 40% share in the new entity.

Citing an unidentified industry insider, Xinhua reported the three energy giants will share the remaining ownership, with CNPC holding 30%, Sinopec 20% and CNOOC 10%.

(Reporting by Muyu Xu, Min Zhang and Shivani Singh; Editing by Kim Coghill and Kenneth Maxwell) ((min.zhang@thomsonreuters.com; (8610) 5669-2105;))