The latest report from the communications regulator shows that An Post continued to fall well short of targets for delivery of mail in the first three months of this year.
ComReg said that 78% of standard post was delivered within one working day, well below the regulator's 94% target. The figure was little changed from the previous year.
ComReg said it was concerned with the lack of improvement over previous quarters and the same quarter last year.
Overall, 98% of mail was delivered within three working days, still short of the ComReg target of 99.5%.
Only 75% of mail posted in Dublin fro delivery in the city was delivered on the next working day, but ComReg says this figure may have been affected by industrial action at two offices.