Proposed new air freight charges in Guernsey are ill conceived and disproportionate, the managing director of Guernsey Freight Services has said.
Mike Gurney said its introduction could cost the industry more than £260,000 a year and see price rises for islanders.
The details of the new charges are due to be released next week before they are debated by the States in March.
The Public Services Department said it was part of a move to raise an extra £1.78m from the harbours and airport.
Mr Gurney said those in the industry were predicting the new charge could cost about £45 per tonne.
He said: "I think at best it will in the long-term increase the cost of postage because Guernsey Post will pick up the largest share of this tax.
"It could mean that headline prices for newspapers change as they did some years back when we paid a surcharge in Guernsey for our national papers, so like the Financial Times have just changed their headline price by 30p you could see that reflected amongst other titles."
Public Services Minister Bernard Flouquet said: "The department has been directed by the States to raise an additional £1.78m a year through the harbours and airport to help fund the capital prioritisation programme.
"The only way we do can that is by increasing existing charges or introducing new ones, and we have looked at a whole range of options.
"Obviously this is a significant amount of additional revenue that we have been tasked with raising.
"The Board's preference, so far as possible, has been to spread this across a range of different services and users, and in doing so we have consulted widely with various different port user groups and businesses."