The Labour Court has ruled that cost-cutting measures being pursued by Irish Rail are unavoidable in order to protect the company and its jobs.
The court is recommending pay cuts of up to 6%, for a period of 28 months, after which they would be restored.
It is also suggested setting up a committee to look at non-payroll savings to try and reduce the burden on workers.
SIPTU said the ruling does take account of some of its workers' concerns, however members have already voted against plans to cut their pay for three years.
It will now meet next Thursday to consider the ruling before holding a ballot on whether to accept the recommendations.