Speaking after unions decided to step away from a collective agreement with aviation services firm Swissport by the end of the year, the official said protests could take the form of gatherings at the airport, but there were no plans to halt work.
"We negotiated crisis measures during the pandemic. Employees accepted fewer holidays, lower salaries and longer working hours, based on the promise that working conditions would return to normal after the crisis," Stefan Bruelisauer of aviation union VPOD told Reuters. "Now Swissport refuses to do that."
The potential protest reflects ongoing challenges facing airports in Europe and beyond as companies try to rebuild operations that were hit hard by the COVID-19 pandemic, prompting layoffs in may places. Now many airports and airlines are struggling to recruit.
Swissport spokeswoman Nathalie Berchtold said the current collective agreement that runs until the end of the year included an obligation to keep industrial peace. Bruelisauer said a strike would only be used as a last resort if all else failed.
Berchtold said negotiations with unions would resume in August and September and Swissport was confident of finding a new agreement by the end of the year.
"The pandemic changed air traffic. There are more flights during peak times and airlines add or cancel flights at short notice," she said, adding this meant Swissport needed more flexible agreements than before the pandemic.
(Reporting by Silke Koltrowitz; Editing by Emelia Sithole-Matarise)