The INO, the Irish Nurses Organisation has called on the Health Service Executive (HSE), Southern Area, to manage the nursing shortage at Kerry General Hospital (KGH).
The INO claims the shortage is now so acute that management is depending on staff to work their days off.
INO industrial relations officer Michael Dineen says unless there is a commitment to provide extra nursing posts, services will have to be curtailed at the hospital.
"Our members within KGH are under severe pressure to deliver an appropriate level of care to the patients in their charge due to staff shortages.
"Management would appear to have abolished their responsibility in this regard as they are refusing to acknowledge the reality of the situation.
"If the present position continues it will only exacerbate the difficulties being experienced as nurses will inevitably leave rather than continue to work in the current environment."
A spokesman for the HSE Southern Area has denied suggestions that there is a crisis in staffing at the hospital.
It insists the hospital has its full staffing according to the whole-time equivalent ceiling and funding levels.
It says shortages have occurred in critical areas such as the maternity and theatre departments, but claims that services remain at normal levels.
"Shortages that occur on a daily basis cannot be anticipated in the main because of staff sick leave or emergency leave on a day-to-day basis. Therefore every attempt is made to ensure full cover by requesting that existing staff provide additional hours; this would be the norm in most hospitals."