The IG Metall launched the first wave of strikes in the German metal and electrical industry, Bild reported.
Workers at carmakers Volkswagen (VW) and BMW joined the protest, which began on Tuesday night. They plan to suspend work across the country.
In Hanover, Lower Saxony, around 200 employees of the battery manufacturer Clarios went on strike.
In Osnabrück, also Lower Saxony, 250 Volkswagen employees are striking. The threatened closure of the plant, which employs around 2,500 people, is not covered by VW’s collective labour agreement. The plant is also considered particularly at risk of shutdown due to the earthquake at Volkswagen.
In Regensburg, Bavaria, protesters unfolded placards in front of a BMW plant. In Ingolstadt, workers are planning strikes at Audi.
In Hildesheim, Lower Saxony, about 400 employees, including those at Jensen GmbH, KSM Castings Group, Robert Bosch, Waggonbau Graaff and ZF CV Systems Hannover, halted their work, according to Bild.
