Workers at three Amazon logistics centres in Germany have joined a strike called by trade union Verdi that will last until Saturday as part of a long-running bid for better pay and conditions.

Unions have staged repeated strikes in Germany, Amazon's second-largest market after the United States, since 2013, hoping to force the ecommerce company to recognise collective bargaining agreements that apply to other retail employees.

Verdi said in a statement on Tuesday that around 1,200 workers had joined the strike that started during the Sunday to Monday night shift at warehouses in Bad Hersfeld, Koblenz and Leipzig, and is due to last until Saturday.

"The work at Amazon is tough, particularly at Christmas time, and the pressure is extremely high. Employees pay the price for Amazon's fast delivery promise to its customers," Verdi said.

An Amazon spokesman said participation in the strikes was very low and the stoppages were not affecting operations.

Amazon employs 20,000 staff across 35 sites in Germany and adds thousands of temporary workers to help cover the Christmas rush.