Unions and management at Bus Eireann are meeting this morning to try and resolve an ongoing row over rosters.
The new cost-saving rosters mean some bus drivers are working 13- or 14-hour days.
Temporary rosters have been in place for around three months, and workers are not satisfied with the implementation process with particular problems in Navan.
Dermot O'Leary, General Secretary of the NBRU, is hopeful they can avoid industrial action.
He said: "We're six months after the Labour Court recommendation, and again it strikes us that the company were not ready for the major change that is expected.
"Against that, and bus drivers in particular want to be driving their buses, they also want a work/life balance, they also want to be able to come to work and go home after a reasonable amount of time, not to be working a 13- or 14-hour day.
"And again that's neither sustainable nor tenable."