A spokeswoman for airports operator BAA said:
Mark Serwotka from the PCS has criticised the reaction to staff over the proposed industrial action
It is eight days to the start of the Olympics, and two unions have announced strikes that could affect the Games directly.
In a row over Government cuts, airport immigration staff have said they will walk out the day before the Games' opening ceremony, threatening further industrial action during the Olympics.
Our Business Correspondent, Glen Goodman, has the details.