An Post had an unwelcome delivery yesterday - criticism of its "unreasonably high" prices for cross-border packages.
ComReg, the industry watchdog, said the €18.50 cost of a one-kilo track and trace letter charged by An Post was difficult to justify.
It noted the cost had risen by 36.5pc in the past four years.
An Post disputed ComReg's finding that the rate is "unreasonably high" and claimed it "reasonably reflects the level and volatility of the underlying costs".
However, the regulator also said six other rates set by An Post need further review.
The criticism came as new figures show Ireland has some of the most expensive charges in the EU, with rates ranging from 33pc to 87pc above the union's average.
ComReg said EU law has provisions for better cross-border parcel delivery services, including a requirement by national regulatory authorities to assess tariffs set by postal operators.
The regulator said figures from the European Commission highlighted how An Post's charges were among the highest in the EU.
They show that the €67 charge for a standard 5kg parcel and the €74 cost for a 5kg track and trace parcel were the highest tariffs of any national postal service.
ComReg concluded that An Post enjoyed high margins on its charges for 1kg track and trace letters, which had been increased by 50c to €18.50 last year.
ComReg said the increase came at a time when An Post could have cut the price.
It said An Post had been provided with details of ComReg's analysis, but no errors had been noted.
However, An Post challenged the watchdog's methodology and claimed the figures were "incomplete and misleading".
The company took issue with ComReg's reliance on its acc-ounts to assess its charges as it claimed they did not provide specific details on costs for each of the tariffs.
In turn, the regulator said An Post had not taken any issue with its methodology when a similar assessment was conducted in 2019.