Oil sector workers of French CGT and FO unions voted on Monday to begin a strike at Exxon Mobil's 240,000 barrels-per-day Port Jerome refinery in northern France, the unions said in a joint statement.
Workers at a port terminal in Le Havre, northern France, which handles large volumes of imported petroleum products, also voted overwhelmingly to strike, the CGT said.
The Port Jerome workers will join the rolling nationwide protest that began in March, aimed at forcing the government to withdraw contested labour market reforms.
The unions said the strike and blockade of the refinery will begin at 0400 GMT on Tuesday.
A spokeswoman for Exxon told Reuters earlier on Monday that production had not been affected by the strike, which has hit output at rival Total's refineries.
(Reporting by Bate Felix, editing by David Evans)