Dublin Bus said last night it would not be providing extra buses today to cater for passengers who would normally travel by rail.
A spokeswoman for Dublin Bus said services would operate as normal and it was not possible to provide additional capacity.
Bus Éireann said it would make every effort to accommodate any extra passengers who planned to use its bus services during the strike but it had very limited additional capacity.
AA Roadwatch has advised motorists to allow extra time for their journeys today as traffic is expected to be heavy.
Private bus operators around the State are running extra services today. Yesterday they catered for thousands of passengers who travelled to Dublin to watch Mayo and Kerry draw in the GAA football semi-final in Croke Park.
Upwards of 100 large coaches left Kerry yesterday morning to ferry fans to and from the match.
More than 15,000 football fans made their way from Mayo to Croke Park as every available coach was pressed into service.
In Galway, there appeared to be minimal disruption to travellers, with no obvious sign of disappointed rail passengers at Ceannt railway station in the city.
A handful of strikers holding placards at the entrance to the rail station off Eyre Square claimed they had been getting good support from members of the public.
Iarnród Éireann is predicting that up to 7,000 mainline and commuter passengers will be affected by the picket on Kent Station in Cork today.
An estimated 5,000 rail passengers were affected by yesterday’s strike at Kent Station with a total of 38 departures having to be cancelled after staff put a picket on the station.
Among those affected were French tourists Jean and Noelle Brignaud, who were due to travel to Dublin where they planned to spend the next three days before flying home to France.
“We were on holidays in west Cork and we did not know that there was a strike... In France we are strong supporters of trade unions so we do not have a problem if it is about defending pay.
“The workers were very nice to us and one offered to walk with us to show us where the bus station is,” said Mr Brignaud as the couple headed for the Bus Éireann terminus.