New figures show income tax, VAT and stamp duty are not delivering as much revenue as the Government expected.
However, exchequer returns published this evening show corporation tax continues to outperform expectations with nearly €650 million - or 18.3% - more than expected raised in 2016 so far.
Overall taxes are 1.5% better than expected, and up 5.7% on a year on year comparison.
For income tax, receipts at the end of September were €114m (0.9%) below annual estimates, but up 4.1% on last year's take.
VAT receipts were 0.4% above expectations in August, but for the year to date VAT receipts are now €278m (2.7%) below targets.
The Department of Finance says the figures "make it clear that the public finances remain on target to achieve revised 2016 forecast, of a general government deficit of 0.9% of GDP, as set out in the Summer Economic Statement".