Update - 4.30pm: The National Bus and Rail Union is to ballot its members at Dublin Bus on industrial action.
It follows today's announcement by Siptu which is to ballot its members this week after a Labour Court recommendation on pay and conditions.
The NBRU said their decision follows an "emphatic rejection" of the Labour Court's recoomendations.
The union is proposing to carry out the ballot on Thursday and Friday this week.
General Secretary Dermot O’Leary said: "It is clear that a mandate for industrial action will be received from Dublin Bus staff over the coming days, given the level of anger reflected in the outright rejection of the Labour Court pay proposals (2.75% per year).
"The recommendation fell short of both the expectations of our members and the level of award issued to resolve the recent Transdev dispute (3.8% per year)."
Mr O'Leary said it "was such that our members are demanding an immediate ballot for industrial action, we will ballot our members over Thursday 4th and Friday 5th August".
He said that staff deserve "a flat, no strings attached pay award at least in line with the public transport sector norm set by the Labour Court in the Luas dispute".
The NBRU statement said: "Dublin Bus have it in its gift to prevent any mandated industrial action by recognising the entitlement of its own staff to pay rises beyond those suggested by the Labour Court, we note the Ministers comments in the aftermath of staff rejecting the recommendation and would suggest that he as the shareholder should encourage Dublin Bus to look again at the level of pay on offer, particularly in the context of all that staff have contributed over two Cost Cutting Plans, inclusive of pay cuts.
The union outlined their options for industrial action:
Industrial action up to and including all-out strike,
24hr/48hr work stoppages,
Work stoppages of a shorter duration,
No fares day.
Earlier: Strike action at Dublin Bus is on the cards, according to Siptu.
The union is set to ballot its members this week after they - along with the National Bus and Rail Workers union - voted to reject a Labour Court recommendation on pay and conditions.
It follows a meeting of the union this morning and the NBRU has yet to announce its next course of action in the long running dispute.
In a statement Siptu says the possibility of industrial action, which will inconvenience Dublin Bus users, is now "increasingly likely".
Siptu's John Murphy, said: "Siptu members in Dublin Bus have expressed anger at the pay increases proposed in the Labour Court recommendation which they overwhelmingly voted to reject last week. Dublin Bus has made significant profits for the last two years and is on target to be profitable, again, this year.
"The workers have not had a pay increase since 2008. They deferred a pay increase of 6% due in 2009 and since then have also implemented several measures that have increased productivity and reduced costs for the company."
Mr Murphy said the implementation of the measures by the workers was crucial to the company’s return to profitability, but he said the Labour court failed to address this in their decision.
He said: "The Labour Court recommendation did not in any way recognise or attempt to redress the sacrifices made by the workers during this period.
"The ballot of Siptu members in the Dublin Bus Traffic Grade will be conducted next week. Siptu representatives are available to meet with the management of Dublin Bus to try to resolve the current dispute. However, the possibility of industrial action, which will unfortunately inconvenience Dublin Bus users, is increasingly likely."