The national finances were in surplus to the tune of €497 million in the four months to the end of April, Department of Finance figures released today show.
The surplus compares to a €1.2 billion deficit in the same period last year.
Tax revenue was €12.8 billion in April, the weakest month so far this year for tax receipts, although revenue was still well above government forecasts, with total receipts at €14.3 billion.
The figures show total government expenditure at €13.8 billion - a statistic that drew sharp criticism from the Opposition.
Fine Gael finance spokesman Richard Bruton said the fall in expenditure showed the Government did not have the competence to keep major investment projects on track.
Mr Bruton said that if the shortfall in spending continues then throughout the year the tax intake for 2006 could amount to over €1.2 billion extra in revenue.
Despite the cash required to address "an utterly inadequate public service and an appalling lack of infrastructure" was not being spent, he added.
"With a history of cost overruns and a failure to fast-track capital programmes, it proves this Government cannot spend money where it is needed, when it is needed.
"Taxpayers will be left wondering what their money is being spent on ," he said.
The Labour Party's Joan Bruton said the figures showed that tax payers were paying for low bands through high stealth taxes.
Value Added Tax (Vat) was the largest contributor to the exchequer amounting to €4.4 billion as compared with Income Tax receipts of €3.6 billion over the first four months.
"The Government is feeding off inflation by having some of the highest Vat rates in Europe."
The Government likes to talk the talk of low direct taxation. In reality, indirect taxation, particularly Vat and stealth charges, are exacting a heavy burden on consumers, particularly people on lower incomes," she said.