An Amazon sign is seen at an Amazon logistics centre in Werne, Germany, December 17, 2018. REUTERS/Leon Kuegeler

By Helen Reid

LONDON (Reuters) -Workers went on strike at Amazon warehouses in Germany on Black Friday aiming to disrupt operations on a key sales day as they push for a collective bargaining agreement, with separate protests also planned outside Zara stores in Spain.

Services union Verdi said around 3,000 workers were expected to participate at Amazon warehouses in Bad Hersfeld, Dortmund, Frankenthal, Graben, Koblenz, Moenchengladbach, Rheinberg, Werne, and Winsen.

Amazon said the strike would have no impact on customer orders and said it paid fair wages. A spokesperson said it has around 40,000 workers at logistics centres in Germany, with an additional 12,000 seasonal workers for the peak festive period.

Separately, unions called for protests outside Zara stores across Europe, demanding a profit-sharing scheme be reinstated.

(Reporting by Helen Reid;Editing by Alison Williams)