New figures from ComReg show that An Post delivered 85% of standard mail throughout the country within one working day last year.
This is a one percentage point improvement on its service quality performance over 2009 but still falls short of the company's targets of 94%.
The figures from the Commission for Communications Regulation also show that 99% of all mail was delivered within three working days. Again this falls just short of a target of 99.5%.
The survey takes account of the severe weather conditions in November and December and ComReg said the periods between November 28 to December 15 and December 17 to December 30 were not included.
'Despite the An Post performance standard of 94% being in place since 2004, a significant deficit still prevails between actual performance and An Post's performance standard,' ComReg said.
