German airline Lufthansa said it is considering legal action after trade union Verdi called on thousands of workers to go on strike on Monday to increase pressure on management in pay negotiations.
Lufthansa said the planned action, which would see workers walk off their jobs for a full day at several airports - including Europe's third largest at Frankfurt - goes far beyond a regular "warning strike" and would cost the airline tens of millions of euros.
Warning strikes are a common tool in German pay disputes and are usually a shorter form of action before an all-out strike is declared.
Lufthansa has used the courts before to prevent strikes going ahead in previous disputes, such as those with pilots and air traffic controllers.
"It's completely out of proportion," a Lufthansa spokesman said. "Especially given that four further dates for pay talks had already been agreed upon."
Staff represented by Verdi have already held a one-day strike on March 21, forcing Lufthansa to cancel nearly 40 per cent of its flights for the day.
Verdi, representing about 33,000 employees, has described a pay offer put forward by Lufthansa management on Wednesday as "scandalous" and said that it would represent a drop in pay in real terms over the next 12