No railway lines will be closed until a full public consultation is made on the future of the network, the National Transport Authority has said.
It comes after a report from the National Transport Authority (NTA) and Irish Rail warned that lines could have to close unless more money is pumped into the company, and that the lack of funding for essential maintenance could be a safety risk.
Fianna Fáil called on Transport Minister Shane Ross to publish the report in full, and said he appeared to have a "complete disregard" for the transport system.
"He seemingly has a complete disregard for our transport system and has no vision for the future," transport spokesman Robert Troy said. "He has completely failed to engage in transport issues since being appointed minister and seems to have little interest in his brief."
The report suggested that a number of services - including parts of the Galway-Limerick line, Limerick-Ballybrophy, Limerick Junction, Waterford and the Wexford line south of Gorey - could be shut. It also said the network needed investment of some €600m over the next five years. The lack of funding threatened the company with insolvency, it said.
This is not the first time that the closure of lightly used railway lines has been suggested. In 2011, an AECOM report for Irish Rail said a number of lines "could be considered for closure", while in 2014 the-then transport minister Leo Varadkar said that unless passenger numbers improved, lines would be closed because many services would "no longer be sustainable".
The Department of Transport said Mr Ross would bring the report to Cabinet next week, and it would be published shortly after to allow a public consultation process.
It said that Irish Rail secured extra funding of more than €50m next year for maintenance and safety projects.
While passenger numbers are increasing, Irish Rail is forecast to lose €11m this year. The NTA said that no decisions would be made about the future of the rail network ahead of a public consultation.
General secretary of the National Bus and Railworkers' Union (NBRU) Dermot O'Leary said while the closure of any lines would raise industrial relations issues, an "open debate" was needed on the future of the public transport sector.
"Politically, there's going to be a problem with it. The NTA and Irish Rail compiled it (the report), they're the ones running the railways and they acknowledge that funding is needed," he said.
"The NBRU have called for an open debate on the provision of public transport for a number of years now, including the shortfall in funding. We need a forum to discuss this issue to include passengers, companies, the private sector, trade unions, the National Transport Authority and government."