Workers at Shannon Airport are to vote next week on whether to take industrial action over the possible loss of 260 jobs at the Co Clare facility.
The ballot by trade union SIPTU was arranged in response to speculation that the Shannon Airport Authority is planning to cut the workforce in half.
A spokesperson for the authority confirmed it was drawing up a business plan, but had not yet put a figure on the number of jobs at risk.
SIPTU has argued that any lay-offs would breach government assurances about job security given in the wake of the break-up of Aer Rianta into three competing companies.