The latest talks between nurses and the Government have ended without agreement.
It comes amid continuing efforts to resolve the ongoing dispute, which revolves around recruitment and retention issues.
Following several days of strike action by nurses and midwives earlier this year, the Labour Court issued proposals aimed at ending the industrial action.
Unions called off three planned consecutive strike days in the wake of the recommendations.
The Executive Council of the Irish Nurses and Midwives Organisation recommended acceptance of the deal.
A ballot was due to take place over the coming weeks.
Union representatives have been in discussions with the Government and HSE over a new contract for nurses and midwives.
However, late last night they said talks had ended without agreement.
"Very large gap"
In a statement, the INMO said there is a "very large gap" between the union and health officials.
They said: "We do not believe that their current proposals would be acceptable to our members, nor do they fulfil the requirements of the Labour Court recommendation.
"This dispute arose over recruitment and retention problems. The employer's proposed contract would only worsen such problems."
Union officials will meet later today for an extraordinary meeting to discuss the 'next steps'.
SIPTU's health division echoed the INMO's concerns.
SIPTU Nursing Sector Organiser, Kevin Figgis, said: "It is our assessment that the totality of the proposals either provide little or no benefit for some nursing and midwifery grades and destabilise the entire concept of a workplace location and a structured rostered day."
Over 40,000 nurses from the INMO and the Psychiatric Nurses Association (PNA) were due to strike when the strike days were suspended last month.
