The Defence Forces are losing staff and not replacing them, with over 1,000 personnel paying to leave in the past five years.
Pdforra, the Permanent Defence Force Other Ranks Representative Association, maintains the Defence Forces are now at their lowest strength in over 30 years and experiencing difficulties in retaining and recruiting personnel.
The group is holding its annual conference in Co Cavan on Tuesday. It will be attended by Minister of State for Defence Paul Keogh and the chief of staff of the Defence Forces, Vice Admiral Mark Mellett.
Association general secretary Ger Guinan told RTÉ’s Morning Ireland that employers regard Defence Forces personnel very highly because they are loyal, hard working and well trained.
The loss of highly trained specialists is particularly acute in air traffic control, bomb disposal and in the naval service because staff are overworked and underpaid, he said.
Mr Guinan said there are currently 9,000 serving in the forces, but its optimum strength is 9,500. A significant number - 500 to 600 - are in training, which means they are not in the front line, putting more pressure on others.
The association says the numbers interested in joining have halved in the last four years, with the majority of those applicants not bothering to complete the entrance test. Only 8 per cent of those who did express an interest joined the Defence Forces, he said.
He pointed out the Army Ranger wing received a pay award in 2011 that has still not been paid.