BERLIN (Reuters) - Trade union Verdi called for workers at a key Amazon AMZN.O logistics center in Germany to go on strike over the crucial final shopping days before Christmas, demanding better pay and conditions for workers there.

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

“Verdi wants to use the high-turnover days before Christmas to raise the pressure for collective wage bargaining at Amazon,” the union said in a statement on Sunday, saying that staff Christmas bonuses should be quadrupled from their current level of 400 euros ($441).

“It’s precisely during Christmas business that colleagues are most heavily burdened, under stress and doing overtime, and that should be recognized with collectively agreed Christmas money,” added Mechthild Middeke, leader of the strike.

The stoppage, at a logistics center in Bad Hersfeld, will begin on Monday morning and last until Saturday evening. The union did not mention any industrial action at other warehouses in Germany.

In the past, Amazon has said levels of participation in strikes was low and that it experienced no operational impact from them.

“Parcels will arrive punctually since most employees will continue to work on customer orders,” an Amazon spokesman said in an e-mailed statement. “For people in the logistics center, Amazon is undoubtedly one of the best employers.”

In July, Amazon announced plans to open a new warehouse this year, bringing the total number of staff in Germany to 20,000 across 35 sites.