The German Industrial Union for Construction, Agriculture and the Environment (IG BAU) said on Friday it intends to extend its strikes in the main construction sector next week.
The industrial action will be extended to the transport infrastructure, the union announced in Frankfurt on Friday after five days of strikes. To this end, construction sites on roads, railways and bridges are to be shut down across Germany, it said.
The construction workers are highly motivated to fight for their pay rise, said IG BAU head Robert Feiger. "We will not let up until the construction companies present an offer that is higher than the arbitrator's award."
In the first week, around 12,500 employees took part in the strikes.
The background to the industrial action is the collapse of collective bargaining in the main construction sector, which employs 930,000 people, at the beginning of May.
After three unsuccessful rounds of negotiations, the arbitrator Rainer Schlegel proposed two-stage wage increases on April 19.
Initially, wages were to rise by a flat rate of €250 ($271) as of May, followed 11 months later by a further 4.15% in the west of Germany and 4.95% in the east.
While IG BAU accepted the compromise proposal, the employers' organizations rejected it at the beginning of May.
IG BAU is now on strike in favour of its original demand for €500 more per month.
