Unions are meeting to discuss a possible all out strike at Dublin Bus.
They say the industrial dispute will escalate, but that an all out strike is the 'nuclear option'.
A second 48-hour Dublin Bus strike is underway.
No Dublin Bus routes, sightseeing tours and Airlink connections will operate today or tomorrow as a result of the dispute.
Nitelink services will not run on either Friday or Saturday morning but will resume on Saturday night.
More than 400,000 commuters across the capital are facing travel disruption as a result.
It is the second of three 48-hour strikes scheduled for this month, with further work stoppages due to take place on the 23rd and 24th.
But according to Owen Reidy of SIPTU, we could see an all out strike.
While Dermot O'Leary from the NBRU hit out at the Transport Minister Shane Ross, saying he never asked Mr Ross to write a cheque, just to help get Dublin Bus to the talks table.
All out strike at Dublin Bus a real possibility according to unions #DublinBusstrike pic.twitter.com/mob6FNP3v8
— Sean Defoe (@SeanDefoe) September 15, 2016
The unions are meeting to discuss an escalation of the strike.
There has not been any progress made with management in the past week.
Newstalk Drive's Henry McKean spoke with one driver on the picket line.
You can hear this interview in full on Newstalk Drive from 4.00pm.
Yesterday, SIPTU members at the company criticised what they say is "the lack of interest" shown by the Department of Transport and management in trying to resolve the dispute.
Workers at the state-owned company were balloted for strike action in July after rejecting an 8.25% pay rise recommended by the Labour Court.
Dublin Bus has argued that this is above the norm of around 2% a year across the public and private sector.
It says industrial action is costing it more than €600,000 each day, and will reduce its ability to fund the recommended pay increase.
Are you affected by today's strike? Read our guide on how to get to work.