The Office of Fair Trading is investigating complaints received about Amazon's introduction of a new pricing scheme for people using its UK site to sell second-hand books and other items.

Amazon.co.uk is pushing sellers to make sure the prices they offer on Amazon are the same as or lower than they offer anywhere else online.

Many sellers offer books or other products on Amazon for a certain price and on their own sites for slightly less - because sales on their own websites are commission-free. The requirement for price parity began yesterday, but will not be actively enforced until 1 May.

A spokesman for the bookseller said:

We are simply asking sellers who choose to sell their products on Amazon Marketplace not to set prices on Amazon that are higher than the prices they sell at elsewhere. Customers trust that they’ll find consistently low prices on Amazon.co.uk and we think this is an important step to preserve that trust. This general requirement already exists for many of our seller agreements in Europe (and all seller agreements in the US) and we’re now introducing it for the remaining seller agreements in Europe.

Sellers range from hobbyists to specialist bookshops which use Amazon as their main online presence.

One bookseller who spoke to us on condition of anonymity said: "There's already a climate of fear - Amazon is brutal and known to throw people off the site with no recourse or appeal. Amazon wants to dominate online secondhand book sales and this will help them. I offer books cheaper on my site because i don't have to give Amazon a 15 per cent commission payment."

Some forum posters believe the new policy will only be enforced against big sellers, because checking every item would be too much of a burden on Amazon's systems.

Amazon's explanation of the change is here.

John Lewis pricing (the chain famously claims to be "Never Knowingly Undersold") applies to all non-physical stores including catalogues, mobile applications or other websites like ebay.co.uk.

The OFT will study the complaints received before deciding whether the market needs a little help or if the problem should be referred to another competition authority. ®