Talks between nurses and the HSE at the Work Place Commission have adjourned for the night.
The negotiations are taking place aimed at averting strike action at seven hospitals across the country.
The INMO says their members will hold rolling, two-hour work stoppages next Thursday in protest at overcrowding.
Talks are due to resume in the morning and spokesperson Dave Hughes says discussions today were frank.
Mr Hughes said: "We had a full opportunity to explain the level of the lack of confidence that the members working in the emergency departments round the country have that management will actually deliver on any of the things that are designed to reduce the level of overcrowding and understaffing in these departments."