Stormont departments are on course to overspend by £660m this financial year, equivalent to almost 5% of the budget.
The Executive had not agreed a budget when the DUP withdrew from the first minister's role in February in protest at the Northern Ireland Protocol.
Departments have been operating without proper budgets since the start of the financial year in April.
Departments had initially been able to operate without a formal budget because of what is known as the vote on account.
It is a legal mechanism which allows the spending of money in the first few months of a financial year before full budget legislation is passed.
Neil Gibson, the senior official at the Department of Finance, has been using emergency powers to release cash to departments.
Section 59 of the Northern Ireland Act allows Mr Gibson to use money, equivalent to up to 95% of last year's budget, "for such services and purposes" as he directs.
If a Northern Ireland budget was not passed at Westminster, Mr Gibson would ultimately have to impose in-year cuts of least 5% across the public service.
Earlier this month, the secretary of state said the findings of the Fiscal Council were "alarming" and he would be working with the Northern Ireland Civil Service to "work through the next steps needed on the NI budget".