A strike in Gabon by oil workers at French company Maurel and Prom has cut production from the Onal Field to 10,000 barrels per day (Mbbl/d) from 28 Mbbl/d normally, according to a statement from the oil ministry late on Oct. 19.

The strike, which started on Oct. 17 and began affecting oil production on Oct. 18, was related to staff being laid off for missing work during a period of unrest after the presidential election, the Gabon oil workers' union ONEP said in a statement.

"On Monday at 3 a.m., certain workers began a strike...despite negotiations that were underway," the oil ministry statement said.

Work has also been impacted at the Coucal oil field, the ministry and ONEP said. ONEP has threatened a general oil strike if the 11 workers were not allowed to return to work.

Gabon is an OPEC member nation and Africa's fourth-largest producer, with an output of about 220 Mbbl/d, dominated by international oil majors Total and Royal Dutch Shell Plc (NYSE: RDS.A).

The strike comes after a disputed Aug. 27 presidential election, which was narrowly won by President Ali Bongo, but which opposition leader Jean Ping said was rigged. Violence followed the results in late August, in which at least three people were killed. The opposition said dozens of people died.

The 11 oil workers left a site operated by Maurel and Prom on Sept. 23, the day that the Gabon constitutional court gave their ruling on the election. Many in Gabon stayed at home that day for fear of further violence.

Maurel and Prom was not immediately available for comment.