Days after the State stepped in to protect the country's banks, Exchequer figures show a deficit of €9.4bn for the nine months to the end of September.
This compares to a deficit of €3.1bn at the same point last year.
Tax revenue for the year as a whole is expected to be €6.5bn less than expected, and it is estimated the Government will have to borrow €11.5bn to pay its bills.
The Minister for Finance, Brian Lenihan, said the slump in the Government finances was a very serious matter.
Speaking on RTÉ News: Six One, Mr Lenihan said Budget discussions were ongoing, but that the State was facing what he called tough decisions.
The Taoiseach has said that this was a defining moment in our nation's history.
We were in extraordinary economic circumstances and if the right choices were not made it would have catastrophic consequences for our future prospects.
Brian Cowen said no one should harbour any illusions that living within our means would be easy in the circumstance in which we now find ourselves, but his Government would not be found wanting in making the necessary hard decisions.
Total tax revenue in the year to the end of September was 11.2% behind expectations at €29bn.
The Government says that the performances of VAT, Capital Gains Tax and Stamp Duty receipts are disappointing and reflect developments in the property market as well as weaker economic activity.
VAT receipts are 6.6% lower than they were at the same time last year at €10.9bn.
Capital Gains Tax receipts are 41.93% lower than they were this time last year at just over €693m.
Stamp Duty receipts are 45.8% lower than figures for last September at €1.35bn.
