German rail operator Deutsche Bahn cancelled two thirds of long-distance passenger services Wednesday as train drivers began an open-ended walkout that will last at least one week.

The strike, the ninth in a protracted dispute, had actually begun on Tuesday, initially affecting freight trains, but was extended to passenger services from 0000 GMT on Wednesday.

It is the latest flareup in a battle over wages, work hours and negotiating rights between the small GdL union and national rail operator Deutsche Bahn (DB).

In early May the union staged a nearly week-long walkout, the longest in DB's history, which industry groups estimated cost Europe's top economy almost half a billion euros ($550 million).

The GdL, which represents some 20,000 train drivers, is demanding a wage rise and shorter work hours as well as the right to represent other rail workers such as conductors and restaurant carriage staff.

That demand is effectively a turf war with the larger railway union EVG, which has more than 200,000 members, and which is now involved in separate, less heated, wage negotiations with DB.

After weekend talks between the GdL and Deutsche Bahn again ended badly, the union on Monday announced the latest strike.

GDL has not said how long the latest walkout will last, but said it will be longer than the six-day industrial action at the start of May.

The union said it would give 48 hours' notice when the strike will end.

Deutsche Bahn confirmed Wednesday that two thirds of long-distance services would be cancelled and an average one third of regional services, varying from region to region.

In freight services, around two thirds would run, the company said.

Eastern Germany was particularly hit. And fewer than half of regional trains in Berlin and in Hamburg were running.

Deutsche Bahn said it would "do everything in its power" to ensure that as many services as possible could run at the weekend, which is the Christian Pentecost holiday.

Deutsche Bahn transports around 5.5 million passengers and over 600,000 tonnes of cargo in Germany every day.