Work will come to a standstill from Thursday’s night shift and throughout Friday, the union said, as part of a dispute that began in 2013 over Amazon’s refusal to recognise industry-wide pay agreements.

A spokesperson for Amazon said participation in the strike was low and the vast majority of colleagues were working as normal, meaning customers will receive punctual deliveries of orders.

The affected centres are in Koblenz, Leipzig, Rheinberg, Dortmund and Bad Hersfeld, Verdi said.

The U.S. company has repeatedly stated that pay, benefits and career opportunities at the company are “excellent.”

“It’s not for nothing that half of our colleagues have been with us for over five years,” the Amazon spokesperson said.