THE Casement Park stadium project cannot proceed without more public funding, the GAA has told Stormont officials.
However, civil servants are unable to allocate any extra money in the absence of ministers.
There are fears the multi-million-pound project could be hit if a power-sharing executive is not restored.
The west Belfast redevelopment is receiving around £62m of public funds and was originally expected to cost £77m overall.
But in its recent annual report Ulster GAA confirmed for the first time the final cost will exceed that amount.
The new projected cost remains unknown, although budgets for other stadium projects suggest it could be significantly more.
It is the latest setback for the sports ground which has faced years of problems and delays.
In 2014 planning approval for the original 38,000-capacity design was quashed in a legal challenge.
A revised planning application was submitted in February with a reduced spectator capacity of around 34,000.
The project has cost more than £9.2 million before construction work has even begun.
Ulster GAA says the proposed stadium will provide "outstanding sporting, community, cultural and economic opportunities".
But residents behind the previous court action remain opposed, saying it is "not a significant reduction" in capacity.
The Department for Communities (DfC) said the GAA's Ulster Council (UCGAA) advised the department last summer that its estimated cost had increased.
"The UCGAA continues to engage with departmental officials on the funding position and they have indicated that the project could not proceed without additional public funding," a spokeswoman said.
"Any request for additional funds submitted to the Department for Communities by the UCGAA will have to be considered by this department and the Department of Finance and will then be subject to consideration and approval in due course by incoming ministers.
"No ministerial decision to allocate any additional funding to the existing financial allocations under the Regional Stadia Programme could be taken before that process has been completed."
The spokeswoman said DfC has asked UCGAA to provide a "detailed breakdown of their projected cost increase" in a finalised business case.
Civil servants in the Department for Infrastructure will decide whether to grant planning permission if no new executive is formed.
SDLP MLA and former GAA All-Ireland winner Justin McNulty, the party's sports spokesperson, fears the project could be "off the cards indefinitely".
"All parties agree that the stadium should be built to give the GAA a new, fit-for-purpose home in Belfast to develop and enhance participation in Gaelic Games in Antrim," he said.
"An increase in projected costs means that a minister needs to approve additional spend. I am seriously concerned that the lack of an executive means that approval cannot be granted and the redevelopment of a new world-class home for Gaelic Games in Ulster will be off the cards indefinitely. That is an unacceptable position.
"I will be raising this matter with the Department for Communities and the GAA to seek a resolution. This is yet another imperative for restoring power-sharing."
Sinn Féin West Belfast MP Paul Maskey said his party remains committed to Casement's redevelopment, saying it is a "landmark project and will greatly enhance the regeneration of the west Belfast area".
"It will also enhance gaelic games throughout Antrim, Ulster and indeed across the island," he said.
Among the setbacks, in 2015 the Casement project underwent a review after a safety expert claimed the initial 38,000-capacity design could not be evacuated safely in certain emergencies.
The revised plans involved a 32-week community consultation and Ulster GAA has insisted it is "confident of resolving all aspects pertaining to safety", welcoming a report last year which it said provided a "positive assessment" of its plans.
But People Before Profit councillor Matt Collins criticised how the project has been handled.
"If you looked up the word 'cock-up' in the dictionary, a picture of Casement Park would likely appear alongside it," he said.
"Let's be clear, no-one is against the building of Casement Park, the question has always been whether the stadium is safe and suitable for the area surrounding it.
"With or without a minister in place, this will only be delivered through proper transparency and bottom-up engagement with the community."
In his annual report, Ulster GAA secretary Brian McAvoy said the board's focus has been on "ensuring the necessary funding will be in place to see through the delivery of the stadium".
He said that discussions "indicate a willingness and commitment from both the GAA and from government to deliver on the obligations of funding agreements and commercial contracts to deliver the stadium".
Ulster GAA was unable to give a new cost estimate. In a statement, a spokesman said: "Given that the Casement Park project is now some four years behind schedule, total costs will exceed those outlined within the funding arrangement.
"We are currently working through those projected cost increases and we will be engaging with DfC throughout the process."
