BENGHAZI, Libya, May 18 (Reuters) - A state oil firm controlled by Libya's internationally recognised government has appointed boards for two state-run oil subsidiaries, officials said on Monday.

The move signals the determination of a new oil firm based in eastern Libya to get a grip on the country's oil sector contested by two rival governments vying for control of the OPEC member four years after the ousting of Muammar Gaddafi.

Libya's official Premier Abdullah al-Thinni has been forced to work out of the east since losing control of the capital Tripoli where the established state oil firm NOC supervising the vital energy industry is based.

Thinni's government has set up a new oil firm, also called NOC and vowed to route payments of oil revenues through it, though industry sources said foreign buyers of Libyan oil are still only dealing with NOC Tripoli.

In a new push to take control of the sector the eastern NOC appointed the boards for two new state oil subsidiaries based in southern Libya, a statement by the eastern NOC said. One company will focus on exploration of oil and gas and a second on building a refinery.

"The two boards will work out technical details for the firms," said Mohamed Araibi, deputy chairman of NOC in the east.

NOC Tripoli has warned the establishment of a new state oil firm in the east might deter foreign customers wondering who is owning Libya's oil and gas reserves.

NOC Tripoli said it is independent, though an oil minister belonging to a rival government controlling Tripoli is working out of the same building.

(Reporting by Feras Bosalum and Ayman al-Warfalli; Writing by Ulf Laessing; Editing by Richard Chang) ((ulf.laessing@thomsonreuters.com; follow me on twitter @ulflaessing; Tripoli newsroom; Reuters Messaging: ulf.laessing.reuters.com@reuters.net))

Keywords: LIBYA OIL/