The HSE has said it is unable to do anything about nurses' pay, as it is signed up to the Lansdowne Road Agreement.
Talks have broken down on ways to address overcrowding in emergency departments, and other issues, including a pay increment.
Members of the INMO are now expected to take to the picket lines from next Tuesday.
National HR director with the HSE Rosarii Mannion said there was progress on key issues, but not pay.
"Significant progress was made in relation to seven issues round insurance, staffing, health and safety, recruitment and retention (and) management structures," she said.
"However, this issue that we were not able to progress satisfactorily was in relation to nurses' pay and incremental credit. Now, this was not within our gift.
"We are signatories, as are many other bodies, to the Lansdowne Road Agreement (and) while we are happy to engage, we are not in a position to advance talks on pay."