The second strike in a matter of days at German flag-carrier Lufthansa is causing disruption at Frankfurt Airport.

Nearly 200 flights have been cancelled at the busiest airport in Germany, as cabin crew represented by the UFO trade union walk out in a dispute over pay and conditions.

Staff are also on strike at Tegel airport in Berlin and at Munich Airport.

Workers held an eight hour strike last Friday, demanding a five per cent increase in pay.

Lufthansa has offered a 3.5 per cent increase, tied to a changes in working conditions.

The union said there had been no pay increases for three years.

UFO also wants guarantees that Lufthansa will not outsource jobs and use more temporary workers, as it has done in Berlin.