Production has been shuttered at TotalEnergies' Gonfreville refinery and Exxon Mobil subsidiary Esso's Port Jerome-Gravenchon refinery due to the strikes, while two others are operating at reduced capacity and two more are offline for repairs.

A spokesperson for Petroineos, which operates the seventh French refinery in Lavera, said they had no information on if production was disrupted at their site.

The action is part of a nationwide movement against pension system changes championed by President Emmanuel Macron that include increasing the retirement age by two years to 64.

Last week, hundreds of thousands of angry protesters - including various labour unions - poured out in to the streets marching against the plan they say is being imposed on them by the government.

Both the Gonfreville and Port-Jerome refineries, located in northern France, can produce about 240,000 barrels-per-day (bpd), the biggest in the country, and supply the Ile-de-France region, where the capital city Paris is located.

The Gonfreville refinery produces the aviation kerosene fuel used by local airports, which have reported difficulties in recent weeks due to a lack of supply.

The civil aviation authority said in a post on Twitter air traffic would be disrupted from Monday until early on Thursday at Paris Orly, Marseille, Bordeaux and Toulouse airports. 

An Esso spokesperson said Friday the company had been forced to halt production at their Port Jerome refinery following the complete blockage of crude deliveries from the Le Havre terminal that started March 20.

The refinery is expected to return to production as soon as supply resumes from Le Havre and the strike has ceased. However, the restart for the port Jerome refinery will take several weeks, they added.

A CGT union spokesperson - which represents workers at various refineries - said that the strike was renewed at both Esso's Fos and Port Jerome sites until Wednesday, and that deliveries from the Fos refinery were blocked and production was reduced.

Force majeure was declared at the Dunkirk LNG terminal, which is set to see renewed disruptions from Tuesday morning to Wednesday morning, as delivery capacity reduced to 70 gigawatt-hours per day (GWh/d), operator Fluxys said.

The duration of the strike will be decided tomorrow, CGT representative Frederic Ben told Reuters.

The three other French LNG terminals operated by Engie subsidiary Elengy have been blocked by the strike since March 7.

(Reporting by Forrest Crellin, America Hernandez and Silvia Aloisi; Editing by Jan Harvey and Aurora Ellis)

By Forrest Crellin