French President Nicolas Sarkozy sent in police to clear access to barricaded French fuel depots on Wednesday as unions kept up their resistance to plans to raise the retirement age.
The government said more than 3,000 of the nearly 12,500 service stations in France were out of fuel.
France's largest oil port, near Marseille, has been under blockade for 24 days, forcing 51 oil tankers to lay idle in the Mediterranean, unable to dock.
Police have cleared access to 21 oil depots since Friday, although a barricade reformed at Donges, western France, on Wednesday.
Strikes halted operations at two of France's three liquefied natural gas terminals, though public utility EDF told Reuters there was no immediate risk of shortages.
Mr Sarkozy said the government would not let the country be paralysed by protests against a pension reform that seeks to raise the minimum retirement age to 62 from 60, and again pledged to push through the measures.
The Senate is working its way through hundreds of amendments to the bill and a final vote is due within days.
The wave of protests drew at least one million people on Tuesday.
Protests have largely been peaceful except for sporadic episodes of violence in the southeastern city of Lyon and in the Paris suburb of Nanterre, where clashes between youths and riot police broke out again on Wednesday.
Youths in both cities burned cars and threw projectiles at police, who responded with tear gas, police said.
Nearly 1,500 people have been arrested so far, the interior ministry said.