Renewed disruption may be looming at Bus Éireann from Sunday in a row over the implementation of new rosters.

The move comes five days after further strike action at sister transport company Iarnród Éireann was averted by a Labour Court recommendation.

It also comes as an announcement on the allocation of certain bus routes to private operators by the National Transport Authority is imminent.

Earlier this year, Bus Éireann staff went on strike for three weeks over proposals for cost reduction measures at the company, which at that point was losing €9.4 million a year and at risk of insolvency.

Part of the deal to resolve the row involved the implementation of new more efficient rosters, with drivers actually driving for 84% of their shift (around 5% more than previously), with a new composite rate of pay of €20.11 per hour incorporating certain premium payments.

However, finalising those rosters is proving problematic, with unions arguing that they impose undue hardship on staff who could have to work shifts of up to 13 hours with inadequate breaks.

The rosters were due to be implemented across all regions on Sunday 30 October, but were deferred first to 12 November, and then again to 19 November.

There have been problems in the eastern region with disruption to services, which unions blamed on unworkable rosters, but management blamed on a spike in absenteeism to 14%.

Yesterday, the National Bus and Rail Union warned Bus Éireann that it will ballot its members for strike action if management attempts to unilaterally impose the new rosters on Sunday.

A Bus Éireann spokesperson said the company has had extensive consultation with unions since last May on the rosters.

She said that while the new rosters had come in, the "rotations" to implement them had not.

She also noted that the countrywide implementation date of 12 November had been agreed at a meeting at the Workplace Relations Commission.

While unions have not instructed members not to work the new rosters on Sunday, it is unclear if staff in all depots around the country will have signed up to them by then.

If not, there could be disruption to services from the weekend.

In a statement, Bus Eireann said: "Bus Éireann have - and continue to be - in dialogue and consultation with unions regarding new rosters.

"Management are currently considering the contents of recent letters received from both SIPTU and the NBRU.

"It remains of paramount importance that these rosters and rotations - which improve efficiency - are introduced as planned and previously agreed, given ongoing financial losses."