Fine Gael Transport spokeswoman Olivia Mitchell has condemned the train drivers involved in the current dispute.
She said the train drivers have had two days of "self-indulgent and irresponsible petulance."
"The drivers involved in this dispute have well-paid secure jobs, so why are they subjecting thousands of people to absolute misery and disruption?" she asked.
"The Labour Court has already found against the drivers on their pay claim," Ms Mitchell added. "Other issues were in the process of being dealt with and, in any event, under no circumstances does it justify the complete disruption of train services. The train drivers have made their point, and must now get back to work."
The Taoiseach said yesterday the action was "particularly disappointing" given the investment that had been made in improving facilities for customers on the Dublin-Cork route.
He said there extensive mechanisms available through the labour relations machinery to sort out this type of issue without causing major inconvenience to the public.
Green Party Transport spokesperson Eamon Ryan TD said: "It is symptomatic of the systemic mismanagement within Mr Cullen's Department that we have yet another industrial action in the transport sector."
"The strike centres on the drivers opposition by rail drivers to the new 'Mark Four' trains. These trains have been scheduled to be introduced for months and it was incumbent upon Minister Cullen to ensure that any outstanding issues were resolved before the introduction of the trains, as suggested by the Labour Court back in January," he said.
"The Minister must now face up to his responsibility to get all parties around the negotiating table and find a speedy resolution to this dispute ." Mr Ryan said.
Platform 11, the national rail users organisation, today said it was "shocked and appalled at the lack comment by the Minster for Transport, Martin Cullen."
"It is imply not good enough for the Minister for Transport to simply ignore what has now become a very serious situation."
Platform 11 called on the Mr Cullen to make a statement to rail customers and to take an immediate proactive approach in bringing a swift conclusion to the disruption.
The Irish Hotels Federation said it was extremely concerned by the potential impact of the train drivers' unofficial industrial action on visitors to the regions and in particular overseas visitors.
Meath Commuter rail lobby group Meath on Track said the last serious rail strike in 2000 resulted in the closure of Kingscourt railway line despite the fact the line had 106-year history of transport freight as Gypsum Industries changed to road transport.
Meath on Track spokesperson Proinsias Mac Fhearghusa said: "Meath and Cavan have seen first hand what prolonged industrial action can do to the viability of railways."