Passengers have been urged to check the Bus Éireann website and the Twitter account for the latest updates.
Most service disruptions today have occurred in the north-west, on the Sligo town service.
The company reported ‘minor disruption’ in Waterford where the W4 city services operated at reduced frequency for three and half hours in the morning, between 9am and 12.30pm. It said the W5 city service will operate at reduced frequency for two hours in the afternoon, between 2.15pm and 4.15pm.
"On our Expressway inter-regional services, approximately 97pc of trips are running to schedule. The cancellations are spread around the network with one round trip cancelled between each of Wexford / Dublin, New Ross / Dublin, Tralee / Waterford and one single trip from Dublin to Ballina. In most cases, an alternative service is available within two hours of the impacted departure.”
In a statement issued to Independent.ie, the company said it “regrettably” informed customers of some disruptions to services today.
The only county Galway route impacted today is one round trip between Castlebar and Headford, it said.
"We estimate that 98.6pc of our scheduled trips are operating today,” the statement said.
"In most cases, advance notice of cancellations is available the day before. For people who have pre-booked their Expressway tickets, they are also notified by a direct email sent to them, typically well in advance of travel, allowing them to make alternative arrangements and transferring to other services operating either side of their intended departure. We very much encourage customers to book ahead at expressway.ie to benefit from a guaranteed seat and priority boarding.
“Typically, service issues arise from a number of factors depending on location. This can include challenges in driver recruitment, driver unavailability often at short notice and more recently difficulty in hiring contractors to support services. This has more impact at comparatively smaller depots.
"Bus Éireann is actively recruiting for drivers throughout the country, and in Cork and Limerick has started to train people with Category B driving licences to gain their Category D driving licence.
"Where it is unfortunately necessary to cancel a service, we manage this to minimise the impact on customers, for example temporarily reducing frequency on higher frequency routes and making every effort to ensure the last service of the day operates."
More than 3,250 trips will be in operation nationwide today.
All the details are on the service update section of the website buseireann.ie by region.