France's hardline CGT trade union voted on Monday to extend a blockade of outbound fuel deliveries from Total's Grandpuits refinery near Paris until January 6.
It is part of nationwide protests against planned pension reforms.
Workers did not vote in favour of halting production, which would continue at a reduced rate, a spokesman for the CGT's oil branch said.
A Total spokesman confirmed the outcome of Monday's CGT vote, adding that the energy group was continuing to use other sites to supply its service stations in the Paris region.
Around 50 Total service stations out of a 3,500-strong network in France were experiencing fuel shortages on Monday.
It compares with around 100 outlets affected before Christmas.
The 102,000 barrel-per-day Grandpuits refinery is one of four crude oil refineries operated by Total in France.
The other three were operating normally on Monday, the spokesman said.
Some fuel was also leaving Grandpuits by pipeline in order to avoid storage capacity being filled, according to Total.
The CGT union has been at the forefront of industrial action against President Emmanuel Macron's proposed overhaul of France's retirement system, with strikes crippling train services for over three weeks.
Unions are planning to ramp up action next week when negotiations with the government resume.
The CGT spokesman said its oil section was planning major protests between January 7th to 10th.
