Psychiatric nurses have been offered a new pay contract with the HSE.
The Psychiatric Nurses Association (PNA), which represents more than 6,000 mental health nurses, has been invited to talks at the Workplace Relations Commission about the deal, which is similar to the deal accepted by the INMO earlier this month.
Under the agreement, some nurses would be up to €5,000 better off.
Both unions staged industrial action earlier this year in a row over pay and working conditions.
The PNA said the crisis in psychiatric nursing shows no signs of easing, with growing numbers emigrating or moving to the private sector.