The INMO says chronic overcrowding at the region's main hospital has led to significant health issues for nurses working there.
It comes as the union has announced its to ballot its members for industrial action, up to and including the withdrawal of labour, following the highest trolley numbers ever recorded in the month of October.
Meanwhile, midwives at the midwest's maternity hospital have confirmed that they will engage in a work to rule later this month.
Figures released by the Irish Nurses and Midwives organsiation show a 26 per cent increase in the number of patients waiting on trolleys at the Region's main hospital.
Nearly 6,300 people waiting on trolleys at University Hospital Limerick between January and October, an increase of over 1,300 on the same period last year.
The union has announced its to ballot its members for industrial action up to and including the withdrawal of labour in response to what they say is the worst figures ever recorded in the month of October.
MidWest Industrial Relations Officer Mary Fogarty says nurses at University Hospital Limerick are no longer physically able to continue working under unsuitable working conditions.
The organisation says action is likely to take place before Christmas if measures to address the overcrowding crisis is not taken in the meantime.
Meanwhile, nurses at the region's Maternity Hospital have notified the HSE of their intention to engage in industrial action later this month.
Union members voted by 97 per cent to take part in a work to rule at University Maternity Hospital Limerick from 8am on November 27th.
Midwives are concerned over what they describe as inadequate staffing levels as well as other issues.
Both issues have been raised in the Seanad by Clare Senator Martin Conway this afternoon.
