Talks will resume today in an attempt to avert a strike at Brinks Allied on Thursday which would disrupt ATM cash supplies.
Today's resumption of talks between SIPTU and the company at the Labour Relations Commission (LRC) will be the fourth attempt to resolve the dispute.
Last Friday, the two sides left the LRC appearing to be no closer to a resolution.
The dispute, which began two weeks ago, has already disrupted cash deliveries to ATMs in Dublin and other areas of the east coast. ATMs in areas where there are no bank branches and in some supermarkets have been affected.
Brinks Allied services about 240 machines, mainly in Dublin and the north-east. Supervisors have continued to service cash machines but have indicated they would not pass a picket in the event of a strike so cash would soon run out.
Drivers at the company have been off the road following an attempt by the company to introduce new security procedures. Workers said these would leave them more vulnerable to attack during armed robberies.
Last week, workers voted by 60 to nine in favour of a strike.
It is believed that if no progress is made today, the union will urge a joint referral to the Labour Court which would mean that both sides would be bound by a finding.
The decision to renew discussions at the LRC on Friday followed an intervention last week by the National Implementation Body, a high level group comprising union, employer and Government representatives.
The company has described the current action as "unofficial industrial action which is unacceptable and totally contrary to normal industrial relations procedures". However, the union has said its workers were willing to return to work but would not be using four new vehicles.
It said members were not prepared to work the vehicles particularly because of the policy to drive away from the scene of an attempted robbery even if it meant leaving a colleague.