Amazon is facing fresh legal trouble after being accused of deliberately manipulating prices in an effort to hold up prices and prevent discounting while also bullying marketplace suppliers where they can sell their goods.

The Association of Consumer Support Organisations (ACSO) has filed opt-out collective proceedings on behalf of more than 45 million UK customers, alleging that Amazon’s marketplace pricing policies forced consumers to pay more for goods sold by third-party sellers.

The claim argues Amazon prevented independent sellers from offering cheaper prices on other platforms, stifling competition and keeping prices higher.

ACSO says this practice effectively protected Amazon’s dominance, while allowing it to charge sellers higher fees that were ultimately passed on to customers.

One Sydney-based supplier told ChannelNews the same tactics are being used in Australia, where Amazon Marketplace enables third-party sellers to reach a wide customer base.

Local distributors claim Amazon management “are bullies” who attempt to dictate pricing.

A Melbourne law firm is understood to be examining the UK action with a view to launching a similar case locally.

Amazon has previously come under scrutiny for its pricing policies. Regulators in the UK, Germany, and Japan investigated the company between 2012 and 2016, prompting Amazon to pledge an end to anti-competitive behaviour. However, ACSO alleges the retailer simply introduced new policies that achieve the same outcome. Current investigations are now underway in Germany, Japan, and Canada.

ACSO founder Matthew Maxwell-Scott said: “Millions of people in the UK make purchases on Amazon every day. Despite claiming to be ‘customer-obsessed’, we believe UK consumers have paid higher prices because of Amazon’s policies. This collective action is about securing redress and holding Amazon accountable for anti-competitive behaviour.”

The claims come as Amazon continues to rank poorly in supplier treatment.

In June, the Groceries Code Adjudicator’s annual survey found that only 66% of the retailer’s grocery suppliers believed it followed industry fair treatment rules, with one in three saying Amazon rarely complied.