Dublin Bus drivers may decide to strike after a recommendation that they should get an 8 per cent pay rise.
Workers were looking for an extra 30%, to put them on the same level as Luas drivers.
However, the Labour Court decided on a lower increase of 8.25% out over the next three years.
The drivers' union will ask members to vote on the pay proposals, but they could decide to strike if the deal is rejected.
National Bus & Rail Union General Secretary Dermot O'Leary said: "Whilst acknowledging the difficulties the Labour Court was presented with in deciding on what level of pay was appropriate, given the eight-year hiatus since bus workers last pay increase and pay cuts that were foisted on staff in the intervening period, it is disappointing that the court has apparently decided not to follow its own guide in not awarding a similar increase of at least 3.8% per year which it awarded to others in the same transport sector as recently as last month in settling the Transdev dispute, we went on record in advance of the resolution of the Luas dispute indicating quite clearly that we would expect similar treatment with regards to Bus and Rail workers, we also said that we required the pay gap between Bus and Tram drivers to be addressed as a component of our members pay claim."
"The NBRU has the utmost respect for the State Institutions that are tasked with resolving industrial relations disputes, however our role in lending a voice to the frustrations of Bus Workers has to take precedence at this juncture, whilst it will ultimately be for our members to democratically decide whether the level of pay reward recommend is adequate, we cannot rule out the spectre of Industrial Action in the coming weeks and months should they reject this recommendation."
SIPTU members working in Dublin Bus are expected to ballot on the acceptance or rejection of a Labour Court recommendation on pay before the end of next week.
SIPTU organiser, John Murphy, said: “SIPTU members across all grades within Dublin Bus will be meeting over the coming days to discuss this recommendation in detail.
“The exact schedule for a ballot on its acceptance or rejection will then be decided.
“The ballot process can be expected to conclude by the end of next week.
“However, it is clear that these proposals fall well short of the pay claim made by our members. Due to this the rejection of the proposal is likely.
“This will mean that if there is not an improved offer made by the employer there is a strong possibility of industrial action by our members in Dublin Bus in the near future.”