"All in all, we're expecting the strike to cost half a billion euros," Eric Schweitzer, president of the German Chambers of Commerce (DIHK) said on Monday.

The Federation of German Industry (BDI) expects the strike to cost "several hundreds of millions of euros," calling it "a poison for a highly developed economy like Germany," according to a press release on its website. The steel, chemicals and auto sectors were particularly vulnerable, the BDI said.

The steel sector is one of Deutsche Bahn's biggest commercial clients, with 200,000 tons of steel being delivered by train every day. "Because the strike has come at such short notice, we weren't able to provide for alternatives," Jürgen Kerkhoff, president of the steel association "Stahl" said Monday.

German manufacturing association VDMA is slightly more relaxed about the strike, as "components and partly assembled products as well as finished items are largely delivered by road," VDMA Managing Director Thilo Brodtmann said Monday.

But the head of VDMA's regional section in the south-western state of Baden-Württemberg, one of Germany's manufacturing hubs, called a six-day strike "unreasonable." He told the German news agency DPA that "this week will be tough, especially in and around the major cities. The situation will put companies under pressure."

This week's strike by the GDL train drivers' union is the eighth time Germany's train drivers have downed tools in the current wage bargaining round that began in January.

Freight trains were due to stop running from 3 p.m. (1300 UTC) on Monday. Passenger trains would be affected from 2 a.m. on Tuesday until 9 a.m. on Sunday.

The strikes have triggered a debate in Germany about how much power small, niche unions should wield and whether there should be one overarching agreement or several separate collective bargaining agreements for a particular group of workers, such as train drivers, depending on the union they are members of.

ng/hg (dpa, AFP, Reuters)