German rail passengers face six more days of upheaval after a small but influential train drivers’ union called on its members to strike for a fourth time in a lingering dispute over pay and working hours.

The Gewerkschaft Deutscher Lokomotivführer, or GDL, rejected a third offer from state-owned rail operator Deutsche Bahn AG and asked freight-train drivers to halt work from 6 p.m. local time on Tuesday. It also called on passenger-train drivers to strike from 2 a.m. on Wednesday until 6 p.m. on Jan. 29.

Deutsche Bahn has made “bogus offers” to try to stall the union’s efforts and “discredit it in public,” the union said Wednesday in a statement on its website.

The extended duration of the strike, following a three-day walkout earlier this month, highlights the increasing hostility between the rail operator and union leaders.

Transport minister Volker Wissing described the strike as “destructive” in an interview with Deutschlandfunk earlier Wednesday and asked both sides to resume negotiations.

Germany’s BDI industry lobby said that the latest action was likely to cause “enormous problems” for companies — particularly in the chemicals, steel, automotive, paper and timber sectors — at a time when Europe’s biggest economy is already struggling to emerge from a period of stagnation.

A six-day strike could trigger losses of as much as €1 billion ($1.1 billion) and also cause “considerable damage to the image of rail as a mode of transport,” Tanja Goenner, the BDI’s managing director, said Wednesday in an emailed statement.

“Doubts about the reliability of rail infrastructure, which has already declined recently, continue to grow and the system is becoming increasingly unattractive for logistics decision-makers,” Goenner added. “This does not bode well for climate policy efforts to transport more goods sustainably by rail.”

Deutsche Bahn had submitted a third offer to the union on Friday, proposing a salary increase of as much as 13% and the option to reduce work weeks to 37 hours from 2026.