With football fans due to flood into France in two weeks for the Euro 2016 championships, pressure is piling on the government as queues at petrol stations lengthen by the day.
Prime Minister Manuel Valls warned the CGT union leading the disruption at refineries and fuel depots that it “does not make the law in France”.
The CGT, locked in an increasingly bitter struggle with the government, has called for its action to be extended Thursday to nuclear power stations that supply 75 percent of the country’s electricity.
The union said late Wednesday that 16 of France’s 19 nuclear stations had voted to join the strike, although CGT official Jean-Luc Daganaud said the effect on power supply would depend on how many workers downed tools.
The union has also called for rallies in major cities, upping the stakes after three months of protests that brought hundreds of thousands on to the streets at their peak at the end of March.
The reforms are designed to address France’s famously rigid labour market by making it easier to hire and fire workers.
But opponents say they are too pro-business and will do little to reduce France’s jobless rate of around 10 percent.
France has nearly four months of fuel reserves and President Francois Hollande told a cabinet meeting that “everything will be done to ensure the French people and the economy is supplied”.
But with five of France’s eight refineries having either halted or slowed production, shortages are becoming acute in many regions and spreading to Paris.
Viviane, a 66-year-old pensioner queuing to fill up her car in Allier, central France, said the situation reminded her of May 1968, when students and workers paralysed the country for two weeks in protest at president Charles de Gaulle’s government.
“I remember May ’68 and I can tell you the shortages were no joke so I am taking precautions,” she said.
Worried drivers were using online apps to find petrol stations that still had fuel, with many limiting drivers to just 20 litres (five gallons) each.
The Ufip oil industry federation confirmed that with around a third of the country’s 12,000 petrol stations running dry, it had begun using strategic reserves.
Ahead of Thursday’s possible strike, one nuclear power plant in Nogent-sur-Seine, around 100 kilometres (62 miles) southeast of Paris, is already operating at reduced capacity.
As well as releasing fuel reserves, authorities stepped up efforts to break blockades.
Watched by 80 striking workers, riot police used water cannon to move burning tyres blocking access to a key oil depot in Douchy-les-Mines near the Belgian border that had been in place since last Thursday.
Oil deliveries will become even more difficult Thursday, with work stoppages scheduled in “most ports” after the CGT call.
The Directorate General of Civil Aviation has recommended that carriers cut flights at Paris Orly airport by 15 percent Thursday.
Transport has been further hampered by a rolling train strike that was due to continue Thursday, and some companies said the fuel blockades were starting to hit their business.
“It’s beginning to get to a critical point,” said Pascal Barre, who runs a logistics firm in Poincy, east of the capital.
“We filled up at the end of last week and at the beginning of this week but our drivers need to fill up again and it’s not possible.”
CGT leader Philippe Martinez has vowed to continue the action until the labour legislation is withdrawn.
The blockades have sparked warnings from oil giant Total, which operates five of the refineries affected, that it will be forced to reconsider its investment plans in France.
Protesters are furious that the government rammed the labour market reforms through parliament without a vote.
But in some rare good news for Hollande on Wednesday, figures showed a 0.6 percent dip in unemployment in April — the first time the jobless roll has shrunk for two consecutive months in the past five years.
Labour Minister Myriam El Khomri said the drop was due to government incentives to boost hiring.