Around 1,500 employees in nine federal states, including Berlin, Brandenburg, Lower Saxony and Bremen, were called to take part in demonstrations and walkouts on Friday morning. That followed action in Bavaria, North Rhine-Westphalia, Rhineland-Palatinate, Schleswig-Holstein and Saarland on Thursday.

"This will result in delays for deliveries of letters and parcels," Verdi said.

Deutsche Post had said after the first round of action on Thursday that strikes were unnecessary and it was doing all it could to get any affected deliveries to customers as soon as possible.

The union is demanding a 6 percent wage increase or more time off for around 130,000 workers at Deutsche Post. The next round of talks is scheduled for Feb. 26 and 27.

Verdi held a series of strikes at Deutsche Post in 2015 in a dispute over pay and plans for a new parcel division. Those walkouts, one of which lasted four weeks, cost the firm 100 million euros (88.2 million pounds) at the time.

(Reporting by Victoria Bryan and Matthias Inverardi; Editing by Edmund Blair)