Workers at Puig's BME:PUIG Vacarisses cosmetics factory near Barcelona will hold a 24-hour strike on May 20 over pay disparities between employee groups, trade union CGT said on Monday.
Puig is in talks with U.S. cosmetics group Estee Lauder NYSE:EL over a potential merger that could create one of the world's largest beauty companies.
CGT said the dispute relates to differences in economic compensation between groups within the same company and accused Puig of failing to address the issue.
Puig declined to comment on the planned stoppage.
The strike will affect all three shifts at the factory, CGT said.
The union also plans to stage protests outside Puig's corporate headquarters in L'Hospitalet de Llobregat, near Barcelona.
Workers could consider further measures if the company does not present sufficient proposals, CGT added.
The Vacarisses plant produces cosmetics and skincare products for brands including Isdin, Charlotte Tilbury, Byredo, Loto del Sur, Dries Van Noten, L'Artisan and Uriage.