Tax receipts have grown at more than twice the expected rate for the second month in a row.
Total receipts at the end of May, at €13.8 billion, are running 15 per cent ahead of the same period last year.
Income tax, VAT, stamp duty, corporation tax and customs and excise duties are all up on 2003, with income tax alone up by almost 22 per cent.
Government borrowing is down by 60 per cent.
The Exchequer deficit is running at €495 million, compared to €1.2 billion in May 2003.
Spending is also behind target, running €703 million behind target.
Fine Gael's finance spokesman, Mr Richard Bruton, said the Government had collected €1,750 million more in taxation in the first five months of this year than in the same period last year.
"This represents an extra €1,400 from each household in the country in just five months, or €300 a month.
"This is because the Government has refused to allow the tax code to adjust to take account of the greatly increased cost of living facing families, much of it brought on by the Government's own actions.
"It is vital that extra tax revenue is used wisely to deliver real improvements in the quality of public services."
Mr Bruton said there was a "vital public interest" that financial procedures be put in place in order to avoid further examples of controversial projects such as the Punchestown Equine Centre, the Kenmare Pier and the National Sports Campus Ireland.
"All of these were outrageous debacles undertaken for crude political reasons. The public is rightly demanding strong compliance from banks on how they use money entrusted to them. It is also time for the Government to introduce compliance standards to be put in place for the stewards of our public finances."