The Irish government has allocated €50m for the redevelopment of Casement Park in Belfast.
The venue will accommodate matches at Euro 2028 as part of the joint-hosting between the Republic of Ireland and the United Kingdom.
Work began yesterday at the venue which has been derelict for over a decade.
The original cost of the redevelopment was €88m when it was first mooted, with €17.5m of that being funded by the GAA and the rest by the Stormont Executive.
But in the intervening decade development costs have risen sharply, leaving questions over what the final bill would be and how it would be met.
There is no current figure on the build out of the 34,500-seater stadium, but it could be anything up to €233m.
The Stormont Executive had committed €71m to the original project a decade ago, but is living within a tight budgetary framework.
As part of a major cross-border funding initiative announced today, the Casement Park project has received €50m from the Shared Island initiative, which will "maximise the benefits" of the Republic of Ireland and the UK hosting games, according to Taoiseach Leo Varadkar.
Ulster GAA president Ciaran McLaughlin said: "This is a tremendous boost for all GAA members today.
"Following on from successful bid by the UK and Ireland to secure Euro 2028 and the recent return of the Assembly and Executive we now have a once in a generation opportunity, to further advance community reconciliation and showcase this great city to the world."
