Demonstrators march through downtown Halle/Saale, Germany, Thursday, March 23, 2023. (AP)
Staff at airports, ports, the railways, buses and subways will walk out across much of the country, the Verdi and EVG unions announced on Thursday.
"We think there will be extensive participation in the strike," Verdi chief Frank Werneke told a press conference.
It follows a series of strikes in recent months in Germany in numerous areas, from the postal service to airports and local transport.
Like in many other countries, Germans are struggling with surging inflation after Russia's invasion of Ukraine sent food and energy costs soaring.
Verdi represents some 2.5 million public sector employees, while EVG represents workers on the railways and at bus companies.
It is rare for unions to join forces to call a strike in Germany, and it follows a series of failed talks with employers in recent weeks.
Verdi is demanding a rise of 10.5 percent in monthly salaries, while EVG is demanding a 12 percent rise for those it represents.
The announcement came ahead of a third round of salary negotiations for public sector workers, which begin on Monday.