DUESSELDORF (Reuters) - A strike by security guards over pay has disrupted travel for thousands of passengers passing through two of Germany's busiest airports, the airports and service workers trade union Verdi said on Thursday.

Around 400 workers walked out of Duesseldorf airport in western Germany, according to Verdi. That resulted in 183 flights being postponed until Friday, the airport said.

At the northern airport of Hamburg 103 flights were canceled, affecting more than 17,000 passengers.

Verdi had called on the private sector security workers to strike from the start of the morning shift until midnight.

A spokesman for Verdi said the union was trying to force employers to put a "negotiable" offer on the table and warned that further strikes would follow if this was not achieved.

Verdi is calling for wage rises of between 2.50 and 3.64 euros per hour for 34,000 security workers in the state of North Rhine-Westphalia, where Duesseldorf airport is located.

In Hamburg the union is calling for a wage hike of 2.70 euros for around 600 security workers.

Works councils estimate that more than 70 percent of the employees work in the lowest wage group, earning just 8.23 euros gross ($11.06) per hour.

($1 = 0.7442 euros)

(Reporting by Matthias Inverardi in Duesseldorf, Writing by Michelle Martin in Berlin, Editing by Noah Barkin)