Amazon has written to Irish and EU customers of its "co.uk" website to inform them of changes in light of Brexit.
The change will see consumers being liable for the cost of returning products unless they are damaged or the incorrect product was shipped.
In an email to customers, the company said it will continue to accept eligible returns "if the reason for return is the result of an error (e.g. if the item is defective/damaged/incorrect), any costs incurred for the return will be paid by Amazon".
But, it said: "Otherwise, any costs incurred for the return including transport costs, as well as any associated import fees of customs, will be payable by the person returning the goods."
The changes will apply to all customers of Amazon.co.uk who have a delivery address in the EU.
The company also pointed out in its email that packages delivered by them may, from 1 January, be liable to "customs duties, taxes and fees".
It has also said that the collection of VAT or an "Import Fee Deposit" may result in a price change at checkout on the website.
UK retailers across the board will have to apply similar changes to customers based in Ireland and other EU countries.
The Competition and Consumer Protection Commission has advised people to be aware of the changes and to shop with EU-based retailers in order to avail of better consumer rights.
In the absence of a free trade agreement on 1 January, EU consumers will not avail of a range of existing EU protections when shopping from UK websites.
They will not be able to refer any disputes to authorities as they have done in the past.