Bus Éireann have announced that they are to unilaterally implement changes to staff terms and conditions.
The move comes after trade unions rejected a cost saving plan to avoid annual losses of €16m.
The company says the changes will ensure the protection of core wages and jobs.
From January 13 next, Bus Éireann is to implement a number of changes to the terms and conditions of its 2,700 directly employed workers.
The employees and the trade unions that represent staff were informed of the decision today.
Bus Éireann says it follows a rejection of an offer to unions to avail of a Labour Court hearing on the company's business recovery plan.
The proposal - drawn up in June - is designed to bring Bus Éireann back to profitability next year - and without which the State owned company says it will face annual losses of €16m.
The changes will include a reduction in overtime rates from 1.5 times to 1.25 times and an increase in the working week for clerical and executive staff from 36 hours to 39 hours.
There will also be a reduction in shift, premium and rota payments - which will be reviewed in 2014 - subject to the company's financial position improving significantly.
Annual leave will be cut three days in 2013, 2014, 2015 - while a range of allowance and expense payments will be reduced by 33.3%.
A Bus Eireann spokesperson says its regrettable that the steps have to be taken - but says they are necessary in order to protect basic pay and jobs.