Travellers using Frankfurt airport face a threat of “massive” disruption due to strike action today.

The GdF union, which represents air traffic control employees, called for workers overseeing operations on the tarmac to stage a walkout from 3pm to 10pm local time.

The seven hour walkout in a row over pay and working conditions will hit Lufthansa flights in particular at Germany’s busiest airport. Unions have also called for an additional 14-hour walkout on Friday.

Lufthansa accounts for more than half of about 1,300 daily flight movements at Frankfurt airport.

The airline has been forced to cancel almost 100 flights today including services to and from Heathrow. A 6.15 am departure from London to Frankfurt is among a number of services also hit tomorrow morning.

The carrier said: “Lufthansa regrets any inconvenience to Lufthansa passengers caused by the threatened strike measures by the GdF union and will do its utmost to minimise impacts on passengers. Passenger support and service has paramount priority.”

GdF said that 200 marshalling staff will strike after failing to reach a wage agreement with airport operator Fraport.

The union’s board member Markus Siebers was quoted locally as saying: “We expect that we will create massive problems for Fraport.”

Fraport board member Peter Schmitz said he was confident at least half or possibly two thirds of scheduled flights would operate.

The company described the strike as “absolutely incomprehensible” and would decide early today whether to take legal action against it.