A new scheme that will allow islanders to use more online outlets has been criticised by the Guernsey Retail Group.
Guernsey Post's myUKaddress service was met with a positive reaction on social media when it launched last week.
It gives Guernsey residents a UK address to use when sites don't deliver to the Channel Islands.
The parcels are directed to Guernsey Post's new Portsmouth hub and then transported to the island.
The company says this service has been designed to give consumers more choice, but the Guernsey Retail Group says it could spell disaster for the high street.
Group Director Martin Search says it is a short-sighted idea, from a States-owned trading body.
"The moment you spend one penny off the island, it goes.
"There are actually two or three countries -Switzerland is one of them - that won't even allow Amazon into their country because they know it can be devastating for the economy.
"These individual trading bodies have to go out and make a profit, and that's what the Guernsey people want them to do.
"But on the other hand, they have to look at the bigger picture.
We are the second-largest, excluding the civil service, of employers on the island and if we didn't have a high street it would be a very sad island indeed."
Guernsey Post said it was also launching an online directory called RockShopper at the same time, which lists local businesses that operate online and offer local deliver.
It said it has introduced a special local delivery rate for retailers.
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