The private contractor responsible for delivering airmail parcels from the United States last night rejected suggestions it was engaged in profiteering amid a public outcry over its controversial charge-on-delivery policy.

General Logistics Systems (Ireland), a Dublin-based subsidiary of Britain's Royal Mail, insisted it did not turn a profit on the tariffs, saying they represented customs and excise tolls.

But managing director Mr Frank McCarthy admitted he was taken aback by the scale of public hostility to the levies, which more than 600 people refused to pay over Christmas and which are generating more than 100 complaints a day.

GLS has drawn the ire of the Revenue, which believes the company may be flouting the law by paying customs fees to authorities in Germany, the original point of entry of airmail packages bound for the the EU from the US. These levies are in turn passed on to Irish consumers when the mail is delivered here.

The Consumers' Association of Ireland is also concerned at the levy, describing it as a worrying development of which the public was generally unaware.

GLS and its sister firms across Europe were awarded the contract to deliver US airmail parcels by the United States Postal Service 14 months ago. Recipients of goods valued over €45 are contacted by phone and informed they will be required to pay an administrative fee, typically between €7 to €9. According to GLS, the administrative fee represents the customs tariffs it must pay in Germany.

The bulk of complaints have been made to An Post, which previously delivered airmail packages and continues to process letters and registered mail from the US.

Chief executive Mr John Hynes has forwarded the objections to the US authorities, believing the outcry will boost An Post's case as it lobbies to become sole agency for delivering overseas post.