The deployable number of troops has fallen by 17%.
The Defence Forces are struggle to find volunteers for overseas missions.
The force is in the midst of a long-running recruitment and retention crisis, which is now having an effect on the number of troops available for overseas deployment.
This number has reduced by 17%, to 6,500, in the last 6 years.
Overseas duty has, traditionally, been voluntary.
Data obtained by The Irish Times under Freedom of Information shows "23 officers lodged appeals after being “mandatorily selected” for overseas duty in 2020."
Ger Guinan is General Secretary of PDFORRA.
Speaking to Kildare Today, he says this situation is the result of a number of long-standing factors.
Ger Guinan joined Clem Ryan on Tuesday's edition of the programme
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