The Psychiatric Nurses Association has said it will be impossible to maintain core services due to the level of early retirements and staff already departed from the sector.
According to a new survey released today by the PNA, up to 400 frontline nurses will shortly retire from the psychiatric services. That represents 9% of whole time posts.
The PNA says that in some areas as many as 10% of nurses are leaving.
PNA General Secretary Des Kavanagh said the departures were in addition to 1,200 psychiatric staff who have left in the last two years.
He said mental health services were not sustainable given that the Health Service Executive was also looking for up to €35m in cuts.
The HSE has said that in relation to the overall number of retirements, key posts will be replaced to deliver essential services.
Speaking in the Dáil, Taoiseach Enda Kenny said it is not the case that people are not being replaced in the health service.
Mr Kenny said there is targeted investment and recruitment with €20m made available in primary care and €35m in mental health.
Enda Kenny said commentator after commentator over the years had spoken about the bloated public sector.
Sinn Féin's Gerry Adams said there will be a perfect storm in Ireland's health services during the transition period because of the recruitment embargo and early retirements.
He said €20bn has been paid to the banks in the year that the Taoiseach has come into office.