The Federation of Private Employees (OIYE) said on Wednesday that its members will go on strike on Sunday to protest the opening of retail stores.
A protest has also been planned on Ermou Street in central Athens at 11 a.m.
A recent change in legislation allows stores to open on seven Sundays a year.
OIYE insisted that Sunday opening is not beneficial to shop owners and employees.
“The overwhelming majority of stores that tried Sunday opening did not even manage to cover their basic operating costs,” the union said.