LIBREVILLE  --  Gabon's main oil union said it may begin a strike as early as Saturday, due to a dispute with the government over whether energy should be on a list of sectors required to provide uninterrupted minimal service.

The strike could halt current production of about 250,000 barrels of crude per day in Gabon, Africa's seventh largest producer, where several foreign oil companies operate, including France's Total.

"Discussions with the government have broken down since Monday," Arnaud Engadji Alandji, spokesman for the National Organisation of Petroleum workers, which says it has 20,000 members, said on Thursday.

"Our strike warning lasts until tomorrow at midnight.  After that, the national office reserves the right to give the order for an unlimited and open-ended strike," he said.

The union said it is seeking to keep the oil industry off a government list of sectors bound to minimum service -- like healthcare and transport -- to allow it to continue using work stoppages as an effective tool in collective bargaining.  "Instituting minimum service under these conditions would be the same for us as a condemnation without appeal," Alandji said.

He said Gabon's oil industry suffers from unequal pay for local workers compared with foreign workers, as well as inadequate protections against overlong work hours.