Lufthansa will cancel almost 900 flights in Germany on Wednesday when airport ground staff are expected to join a strike called by the country's biggest services union, Verdi, the carrier said.

Some 87,000 passengers will be affected and 895 Lufthansa flights scrapped because of the strikes at Frankfurt, Munich, Duesseldorf, Cologne/Bonn, Dortmund and Hanover airports, it said.

The walkouts are being staged by Verdi members working in air safety control, ground services, at check-in counters and in engineering workshops at the airports.

They are so-called "warning" strikes intended to increase the pressure in a battle the union is fighting over public sector wages with local and federal governments.

Similar stoppages

Wednesday's strike follows similar stoppages Verdi has recently organised in other institutions, including hospitals, town halls and child care centres.

Lufthansa blasted the walkouts.

"We are not involved in the dispute, but we're being affected the most," the carrier complained.

"It is unacceptable that our passengers are the ones feeling the effects of the strike," said Lufthansa's personnel chief Bettina Volkens.

"Verdi is hurting an airline that offers its workforce the highest welfare standards," she added.

Lufthansa has been repeatedly hit by strikes over the past year in wage disputes of its own, with both pilots and cabin staff staging a number of walkouts over pay and early retirement provisions.

Lufthansa said it has cancelled 545 flights arriving and departing from Munich, with 54,000 passengers affected.

In Frankfurt, where the stoppages would last until 3:00 pm (local time), some 350 flights and 33,000 passengers would be grounded.

In all, Lufthansa said it would only be able to uphold around 40% of its regular schedule on Wednesday, with just 500 flights taking off and landing in Frankfurt and 90 in Munich.

It did not specify how many flights would be cancelled at the smaller airports of Duesseldorf, Cologne/Bonn, Dortmund and Hanover.

Lufthansa advised passengers to check the website to see if their booked flight was taking place.

Longer wait  

On domestic flights, passengers could exchange their tickets for rail tickets. Other passengers would be able to re-book their flights free of charge.

Fraport, which operates Frankfurt airport, said passengers should expect longer waiting times at security checkpoints and contact their airline before coming to the airport.

Despite the protracted industrial disputes last year and the Germanwings crash, Lufthansa saw its profits soar last year on the back of low oil prices and booming passenger business.

Investors mostly took the news of more strikes in their stride and Lufthansa shares were showing a modest loss of 0.1% in early afternoon trading on the Frankfurt stock exchange in a slightly softer market.