Lufthansa cabin staff will go on strike on Thursday and Friday, their union UFO said, warning of more stoppages next Monday if the German airline's management fails to "react appropriately".

"We hope that this will finally bring serious movement in this labour dispute and that we will not be forced to also strike in December," UFO chief Nicoley Baublies said Monday of the long-running battle over pay and retirement provisions.

The union has not specified which airports would be affected, but said it would not hold any walkout during the first Advent weekend of November 28 and 29.

Lufthansa voiced "great dismay" at the new round of stoppages that come just two weeks after a week-long strike -- the worst in the German airline's history with 4,700 flights scrapped and 550,000 passengers grounded.

"We are very disappointed that there is no willingness for dialogue on the side of the union, even though it is clear to all that we can find a solution only if we hold discussions," said Lufthansa's human resources chief Bettina Volkens in a statement.

The dispute erupted nearly two years ago when management sought to cut costs, saying the current retirement system was too expensive to maintain.

The union however wants the status quo to remain.

The conflict with cabin staff is separate from another long-running battle between management and pilots over the company's plans to change the pilots' early retirement arrangements