Oil major Shell said on Friday it could not make any further concessions on pension demands by workers planning to go on strike at its 418,000 barrel per day Pernis refinery in Rotterdam.
Shell said management had sent a letter to the Netherlands' biggest trade union saying "the room for further concessions has been exhausted" after a year of negotiations
"It is highly surprising that the unions have decided to take arms against a proposed scheme which, as the unions must be aware with their professional insight, is one of the best on the Netherlands," a letter by management to the union said.
There was no immediate reaction from the union, which says the Pernis refinery, Europe's biggest, will start shutting down on Monday evening if the workers' pension demands are not met.
The union says it wants no change to the present scheme, while Shell plans to raise the retirement age to 65 from 60 and force workers to contribute to their pensions.
"We will go on as planned. Our ultimatum expires on Monday at 6 pm. We would welcome a call from Shell over the weekend," a spokesman for the FNV union said.