There are now 8,751 serving permanent members of the Defence Forces, new figures show.
That is over 700 less than the recommended level and a new record low, according to Fianna Fáil.
It also marks a drop of 300 personnel since May 2017.
The figures from May pre-date the recent Public Pay Commission Report on the Defence Forces.
However, the party's spokesperson on Defence, Jack Chambers, says he is not convinced its recommendations will solve the crisis.
He has expressed concern that the numbers may be slightly inflated.
“Bear in mind that it is likely that some 500 or more personnel are in training so the effective strength is probably closer to 8,000”, said Deputy Chambers
“We now have a Defence Forces which is 749 members below its approved establishment strength of 9,500. This has happened despite ongoing recruitment campaigns over the past three years. It shows the extent of the retention crisis that the military is experiencing.
“While these figures obviously pre-date the recent publication of the Public Pay Commission Report on the Defence Forces, I am not convinced that the recommendations contained in that report are likely to stem the exodus.
“The exodus we see is the response of people who are willing to put their lives on the line to protect their country but are clearly not valued by the Taoiseach or his Minister of State," he said.