Workers at Portugal's oil company Galp plan to halt the country's two refineries and other Galp installations between April 19 and 21 if their wage demands are not met, a union leader said on Thursday.

The two refineries, in Sines and in Porto, have a total capacity of about 300,000 barrels per day. Ribeiro dos Santos, coordinator of the oil, gas and chemical industry workers' union Sinorquifa, said the company had been trying to assure that minimum production levels are maintained during the strike.

"But we considered that unacceptable and will proceed with the full stoppage," he said. Still, he said the union was open to further salary negotiations with Galp.