Taoiseach Simon Harris has said the €50m pledged by the Government to the redevelopment of Casement Park in Belfast will remain in place "regardless of the decision around Euro 2028".
Mr Harris said he understands the disappointment but that he knows the British government "wouldn't have arrived lightly" at the decision.
"What I have heard from people in recent days is, Casement is still going to happen, it has to happen," said Mr Harris.
"Even if it is not going to be ready for the Euros, I think we now need to now look at how we can [keep] momentum going here, in terms of a forward-looking plan that delivers a stadium, and delivers for the GAA and delivers for sports needs in the North.
"We remain absolutely committed to helping with this."
Mr Harris said that while Casement Park is a decision ultimately for the British government and the Northern Ireland Executive, the Irish Government remains committed to helping with the project.
Minister for Public Expenditure and Reform Paschal Donohoe said it is too early to comment on whether the Government would be willing to pledge further funds to the project.
Speaking on RTÉ's This Week, Mr Donohoe said the commitment to Casement Park will be honoured at "the right point".
He said the Government wants to honour its commitment, but that the Northern Ireland Executive and British government had to deal with the matter first.
GAA 'very disappointed' over Casement Park decision
It comes as GAA President Jarlath Burns said they are "very disappointed" by the UK's decision on Casement Park, but it does not stop their commitment to getting the stadium rebuilt.
"It is just one of many disappointments along this journey to try and get Casement Park rebuilt as a centre of GAA in Belfast," he said.
He described how the Tory government approached the GAA last year with this "wonderful visionary offer" to host some of the games for the Euros.
He said in the last few months of government they were "visibly stalling and not getting the tender documents out and not really honouring the commitments they had made to the GAA. So, that is probably where our disappointment really is."
He believes the Labour government acted in "best faith" and "did do their best, but ran out of time".
Read more: UK govt will not fund Casement Park redevelopment in time for Euro 2028
Mr Burns said they are now calling on the UK government to provide funding for the stadium to be built.
"What we are asking the Labour government is to provide us with a sum of money that you are going to pledge to us, as said you would, to get Casement Park built to the specifications for an Ulster final that can hold 34,000 people"
He said they set out to build a stadium in west Belfast that can take big games and be a centre for the GAA in Ulster.
He said people have waited patiently for a long time and the focus now must be on creating a stadium for Ulster finals and for big GAA matches.
Additional reporting: Marty Morrissey
