The INMO executive council is set to meet on Wednesday
Negotiations over measures to address staffing and recruitment in nursing have adjourned without agreement.
The INMO claim this is as a result of a "total management row back on their previous commitment" for a funded workforce plan for 2017.
The nursing body says it has advised Health Service Executive (HSE) management that proposals have to be radically improved to form the basis of any further discussion.
Talks - which involved the HSE, Department of Health and SIPTU - have been taking place over the past three weeks.
Unions want to secure new initiatives which would begin restoring the nursing/midwifery workforce to at least 2007 levels.
The INMO say health service management refused to allow directors of nursing and midwifery fill all posts which become vacant during 2017.
It says the net effect of this is that the crisis remains and "will continue to destabilise the delivery of safe patient care."
The INMO executive council is set to meet on Wednesday to consider the current position in the context of a recent national ballot for industrial action.
"Unless there is a radical improvement in the next 24 hours it is probable that the executive council will, in the context of this adjournment, take a collective decision to serve notice, for industrial action, on all health employers", the INMO adds.
While SIPTU sector organiser, Kevin Figgis, said: "The management presented the unions with a paper that falls way short of our members’ expectations regarding the protection of nursing and midwifery services into the future.
"The HSE must revisit its position if it is to successfully reach an outcome that is in the best interest of patients and staff alike."
SIPTU organiser John McCamley added: "The debate and discussion over the last eight days was robust and it is unfortunate that we have reached this impasse."