Production by the country's crucial metal and electrical engineering industries may be affected next week by the walkouts after the latest round of negotiations ended without a deal.
The main sticking point remains the powerful IG Metall union's demands for workers to have the option of a 28-hour week, with employers making up some of the salary loss.
“Obviously employers do not understand any language other than pressure,” said Roman Zitzelsberger, the chief negotiator for IG Metall, which represents more than 3.9 million workers.
The union's boss Joerg Hofmann said up to 50 companies would be affected between Wednesday and Friday by the 24-hour strikes in selected sites across the country.
In a statement, the regional employers' association Suedwestmetall warned against solutions that would inflame the situation and denounced the “disproportionate demands” of the union.
The full-day walkouts are a recent addition to the union's arsenal, which has never used them before.
Europe's biggest union has also raised the prospect of staging its first open-ended strike since 2003.
It mobilised more than 600,000 workers in a series of short warning strikes earlier this month, including at Volkswagen, BMW, Bosch and Siemens.
The biggest hurdle in the talks is IG Metall's insistence that employers top up the salaries of some of the workers who choose to reduce their hours.
Employers have slammed the demands as too costly and even discriminatory to staff already working part-time without additional compensation.
They have also so far only offered a two-percent wage increase, rather than the six percent sought by the union.