Rail passengers could face disruption next month due to possible industrial action in a dispute over pay.
The National Bus and Rail Union say they have put Iarnród Éireann on notice that unless a tangible offer is made to its workers they will undertake an immediate ballot for industrial action across the country's railways.
In an address to his union's conference in Co Meath, General Secretary of the NBRU Dermot O'Leary said unless something substantial is on the table, the NBRU will not be a party to what he called abusing the Labour Court by going back and asking it to do what he described as 'the impossible'.
He said the only alternative open to them at this juncture will be to undertake an immediate ballot for industrial action across the railways.
Both sides are due at the Workplace Relations Commission next Wednesday.
The NBRU is seeking pay rises of about 3.75% annually, which it believes should not be linked to extra productivity.
The claims are similar to levels of increases secured by staff at Luas and Dublin Bus.