Minister for Transport Tourism and Sport, Paschal Donohoe TD, condemned the threatened industrial action at Irish Rail.
Members of the NBRU and SIPTU are holding five days of stoppages, in protest at planned pay cuts.
The proposals were accepted by three other unions, the TSSA, TEEU and Unite.
A 48-hour stoppage begins on Sunday and two of the strike days in September coincide with All-Ireland finals.
“It is extremely disappointing that the threatened industrial strike action planned to commence at Irish Rail on Sunday looks set to go ahead," said Minister Donohoe.
“Every effort has been made over 20 months of negotiations, with a number of interventions by the State’s industrial relations machinery, to resolve the matter.
“The action being taken by SIPTU and NBRU members will result in massive disruption on a number of fronts; it will cause considerable inconvenience to rail users, it puts jobs at risk at Irish Rail, and it will add to the further deterioration of the company’s financial situation.
“There can be no winners if this strike action goes ahead. It will contribute nothing to the company’s prospects or to furthering its role in serving the public.
“I am appealing to the unions involved to call off the actions proposed, even at this late stage, in the interest of the future viability of Irish Rail.
“Given that industrial action now looks set to go ahead, I also welcome the fact that the CEO of Irish Rail, David Franks, will return to Ireland this weekend.”
The company says it needs to make massive savings to protect the future viability of the company.
Mayo Fine Gael Councillor Patsy O'Brien, who works for Irish Rail, told Mid West Radio the company chose the date to implement the pay cuts.
"We all regret that industrial action is schedule there on Sunday next - but there has been quite a lot of misinformation out there in the public domain in relation to this," he said.
"This has been ongoing for quite a while; the company picked the date to cut the wages in CIE on that particular day, even though they had a balance since the 25th of July which they could have easily done.
"But as far as I can see they drummed up public support in relation to matches and everything to put the public against the workers in Irish Rail."