A major Defence Forces recruitment campaign resulted in a net increase of just three members.
Fianna Fáil leader Micheál Martin quoted the figure in a Dáil exchange on Wednesday with the Taoiseach Leo Varadkar.
Mr Martin said that between January 1st and December 31st 2017, a "significant recruitment drive" by the Department of Defence yielded a net increase of "three personnel to the Defence Forces".
"We have been telling the Government about the issue for between two and three years", he said.
"The low level of morale within the rank and file, the shabby manner in which they are treated, the gaps in middle management and the failure to retain and nurture specialist expertise within the forces all point to a failed policy of the Government and a Minister of State who, with the Government, is completely out of touch with the reality on the ground.
"In the Army, the Air Corps and the Naval Service, a consistent message emerges.
"Members are exiting the Defence Forces at all ranks, at a rate of between 40 and 50 per month.
"We learned last October that ships could not set sail because there were not enough crew members to manage them. The Air Corps operates at 70% capacity," he said.
Mr Martin said the current strength of the Defence Forces is approximately 8,800 - not taking into account 670 members overseas or 450 in full-time training.
Mr Varadkar responded: "Recruitment is going well. The biggest classes ever are coming through and being attested.
"For the first time, we have people coming up from the non-commissioned ranks to become officers.
"Promotion opportunities are there that were not there in the past.
"There is a particular focus on recruiting more women to our Defence Forces and we are seeing some good results in that regard.
"However, there is a high turnover rate of approximately 8% a year, whereas 5% would be more normal."
"We are doing four things to address it. They include pay restoration, which is happening across the public service, with the next tranche kicking in in the next few weeks."
Mr Varadkar also said: "We are investing in our Defence Forces and increasing the budget this year, with more than €50m being invested in barracks, equipment, pensions and pay.
"While I acknowledge there is a problem with retention in the Defence Forces, recruitment is going well.
"There are record numbers in the classes being attested and graduating, although many people are leaving because there are now many opportunities in the private sector, as the Deputy will know is the case in his constituency in Co Cork, where engineers are leaving the Naval Service to work in the private sector."