New Exchequer figures show the Government recorded a deficit of €823m to the end of June.
This compares to a surplus of €2,485m for the same period last year.
But the Department of Finance says when adjusted for an AIB share sale in June 2017, the exchequer balance has an annual decrease of €323m.
Meanwhile tax revenues are up 5.4% year-on-year to €24,941m.
Gross expenditure on public services and infrastructure is also up 7.6% year-on-year.
The Departments of Finance and Public Expenditure claim the second quarter tax revenues "provide a level of confidence that the Budget 2018 target of €54,175m will be achieved."
Non-tax revenue of €2,466m was up 12.5%, or €273m, year-on-year due to an increase in the surplus income from the Central Bank.
Capital resources of €969m were down 75.5% - or €2,990m - year-on-year, after a base effect of the AIB share sale last June.
Corporation tax in the period ending in June stood at €4,032,885 - up from €3,519,533 at the same time in 2017.
That figure is just over 9% ahead of targets set by the Department of Finance.
