The Ulster Unionist Party has called on the GAA to increase its contribution to the building of a new stadium at Casement Park in west Belfast.
No agreement has yet been reached on the payment plan for the project, which is expected to cost at least £110m.
The initial cost of the project was estimated at £77.5m, with the GAA agreeing to pay £15m of the total.
However, a series of delays has led to an increase in cost, with at least £32.5m extra now required.
The Ulster Unionist Party (UUP) insisted that if the GAA (Gaelic Athletic Association) is not prepared to increase its financial share, it should consider reducing the size of the planned 34,500-capacity stadium.
The Department for Communities, which is overseeing the project, said it is too early to finalise the funding arrangements.
However, the UUP said the onus is on the GAA to come up with the extra money.
The party's sports spokesperson, Andy Allen MLA, said: "The reality is that the Casement Park project has already been allocated £62m of public money, which is more than football and rugby combined received for the redevelopment of Windsor Park and Ravenhill.
"To expect the public purse to come up with another £33m is simply not viable."
He added: "The GAA needs to cut its cloth to fit its budget. If the GAA wants a 34,000 stadium then it - not the public purse - needs to make up the difference between the £62m that was promised by the executive under the Regional Stadia programme in 2012 and what the GAA wants to spend now."
'Remain in draft'
In response, an Ulster GAA spokesperson said: "The funding agreement committed the GAA to £15m, and any variation in that position will have to be by agreement of both the Department for Communities and Ulster GAA."
In October last year, it was announced that planning approval for the stadium had been recommended after detailed consideration.
Later that month, the then Stormont Minister Carál Ní Chuilín said the GAA should consider increasing its financial contribution.
The Department for Communities says the full planning process has yet to be completed.
A spokesperson said: "Officials are working with their counterparts in the Department of Finance and the Ulster Council GAA project team, as they finalise updates to their Casement Park draft full business case, which will remain in draft until all matters associated with the planning process are concluded."
In a draft budget announced by Stormont Finance Minister Conor Murphy earlier this week, an initial £20m was allocated to the Casement Park project. The money is part of the previously announced funding.