The airline had previously anticipated that it would have to cancel 110 flights from and to Munich.
“We've cancelled more flights so that we can have planes in position where we need them so as to resume normal service as quickly as possible after the strike,” a Lufthansa spokesman told The Local.
The spokesman added that 15,300 passengers would now be affected by cancellations.
Plans had been drawn up to make sure that passengers travelling through other Lufthansa hubs, such as Zurich, Vienna, Frankfurt or Brussels, would not be affected.
All intercontinental flights from Munich are operating with Lufthansa staff not taking part in the strike.
Munich Lufthansa manager Thomas Klühr called the strikes in recent weeks “extremely annoying,” especially for Lufthansa customers.
“We can't allow a single professional union to cripple whole companies,” he said.
Passengers affected by the strike can change their booking or cancel for free and have the option of taking the train instead if their journey is within Germany. Hotel rooms are also on offer in Munich.
A three-day strike in April cost Lufthansa €60 million, and the airline is anticipating seven-figure damages from Wednesday's industrial action.
Pilots are to strike between 10am and 6pm in the fourth walkout in five months. The Cockpit Union and Lufthansa blame one another for the failure of negotiations over the company's plans to raise pilots' retirement age.
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