Verdi said in a statement it had called out workers to strike at a distribution centre in Bad Hersfeld, saying Amazon was increasing order volume and pressure on workers with special offers ahead of Christmas.
Verdi expects up to 450 workers to join the strike on Monday, a spokeswoman said. The union said it would keep up the pressure as long as Amazon did not meet its demands.
Amazon said the vast majority of workers had not walked off the job and were working hard to meet customer expectations. It said its deliveries should not be disrupted as it can draw on a European network of 28 warehouses in seven countries.
The U.S. company employs almost 10,000 warehouse staff at nine distribution centres in Germany, its second-biggest market behind the United States, plus more than 10,000 seasonal workers.
Verdi wants Amazon to raise pay for workers at its distribution centres in accordance with collective bargaining agreements across the mail order and retail industry in Germany and has organised several stoppages since early 2013.
Amazon, however, has rejected the demand, arguing that it regards warehouse staff as logistics workers and says they receive above-average pay by the standards of that industry.
© Thomson Reuters 2014