Nurses at the region's maternity hospital look set to engage in further industrial action.
It follows a ballot of union members, the results of which are expected to be known later today.
The action, which is expected to take the form of a work-to-rule, follows a breakdown of talks at the Workplace Relations Commission.
Midwives at University Maternity Hospital Limerick say they are concerned over what they describe as inadequate staffing levels as well as other issues.
In a statement to Clare FM, UL Hospitals Group expressed disappointment over the expected action saying it has the potential to cause disruption and will require careful planning around contingencies.
But a spokesperson from the INMO says no formal decision has been made with the results of a ballot expected to be known later today.
It comes at a time when the region's main hospital in Dooradoyle experienced a significant spike in overcrowding.
30 people were waiting on trolleys in the emergency department of University Hospital Limerick yesterday, while a further 28 were being accommodated in overflow areas of wards.
