Talks aimed at averting next week's all-out strike at Bus Éireann take place today.
The Workplace Relations Commission has invited unions and the company to separate talks to see if there is room for a resolution.
The NBRU and SIPTU are opposed to the company's cost-cutting plan, which will see the reduction of staff pay and bonuses.
Bus Éireann claims the measures are needed to save the troubled firm from insolvency.
Dermot O'Leary of the NBRU says the cuts are unacceptable.
"This is a State-owned company, it's owned by you and I, the taxpayer," he said.
"It's proposing to take up to €8,000 of pay from people, in some cases who are on 42 or €43,000 - that's not tenable, it's not sustainable."