An Post last night rejected claims in a new report that only three quarters of standard letter mail arrived at its destination within one working day.
The ComReg report, published yesterday, measured An Post's quality of service performance during the first nine months of the year.
It said that between January and September 2004, 73 per cent of standard letter mail was delivered within one working day, well short of the 94 per cent target set by ComReg. Some 96 per cent of mail arrived within three working days.
According to the report, "the service throughout the period measured falls significantly short of both the required standard of service set by ComReg and international best practice."
Conducted by TNSmrbi, the survey is based upon the statistical methods set out by CEN, the European Standards Institute.
However, the results were last night rejected by An Post, which said the figures were "distorted and fail to give an accurate indication of the entire market".
A spokesman for An Post said: "We reject these figures. They are based on only a small subset of our output, whereas our own figures suggest the next day delivery rate was closer to 90 per cent.
"These figures are inaccurate and completely undermine the position of the company."