The union said that more than 2,500 sector employees working in five regions had downed their tools overnight to agitate for a 6.5% pay hike, calling employers' offer of 3% over 14 months a provocation.

Work to be taken serious
Mr Berthold Huber chairman of IG Metall said that "We are calling for an offer that takes employees and their work seriously."

Among the big industrial companies hit were truckmaker MAN in Augsburg, industrial conglomerate Siemens via its Osram unit in Berlin, heavy industry giant ThyssenKrupp in Andernach and automotive parts suppliers Continental and Bosch.

Plans massive strike
IG Metall said it plans massive, country wide strikes from mid week.

Read more: Damstahl: Struggling German stainless market

The wage negotiations in the electrical, engineering and metalworking sectors, which employ more than 3.5 million people in Germany, are the bellwether for other key industrial sectors. Talks are currently in a third round in Germany, Europe's top economy, which has weathered the euro zone debt crisis better than most of its neighbors.

Earlier in April 2012, after several weeks of negotiations interrupted by warning strikes across the country, the 2 million people working in Germany's public sector secured a 6.3% pay hike for two years.