Online platforms like Facebook, Google (GOOGL) and Truspilot (TRST.L) have been accused of failing to "filter out fake reviews" that have infiltrated the sites, according to a report from consumer group Which?.
As part of an investigation, Which? found that it was easily able to use a fake reviews broker to supply numerous inauthentic positive reviews for a fictional business on all three platforms.
One broker claimed to have created thousands of fake reviews, telling Which? they made nearly 16,000 reviews for more than 550 customers around the world.
"Facebook, Google and Trustpilot are failing to do enough to shut out a fake reviews industry that has been thriving and profiting from misleading reviews for years now," said Rocio Concha, Which? director of policy and advocacy.
"Facebook in particular has repeatedly been slow to act in tackling fake reviews, showing a complete disregard for consumers who want to read genuine reviews."
The average UK household spends around £900 ($1,090) each year that’s directly influenced by online reviews.
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So far more than a thousand fake reviews have been removed by the three platforms in the wake of the investigation, Which? said.
It comes after the government outlined plans for a Digital, Competition and Consumer Bill earlier this year, which would crackdown on fake reviews.
Responding to the investigation, a spokesperson for Meta (META), Facebook’s parent company, said the company is "investigating the accounts brought to our attention".
"We have dedicated extensive time and resources to tackling this issue and will continue to do so. Fraudulent and deceptive activity is not allowed on our platforms, including offering or trading fake reviews."
Meta said it requested further authentication from the accounts, adding that its safety and security teams were continuously working to help prevent these practices.
Google said it uses a combination of human operators and technology to closely monitor fraudulent content around the clock.
A spokesperson for Google, added: "Our policies clearly state reviews must be based on real experiences, and when we find policy violations, we take swift action ranging from content removal to account suspension and even litigation.
"We encourage users and business owners to flag suspicious activity to us, which helps us keep the information on Maps accurate and reliable.
"While a vast majority of our reviews are authentic, our work to stay a step ahead of scammers is never done, and in this case our teams are continuing to investigate, removing content and blocking accounts associated with malicious activity."
Trustpilot said that it was continually working to ensure it was taking appropriate action against attempts to manipulate reviews on its platform, including reviews written by review sellers.
"In the last 18 months, we have introduced new technology that allows us to understand complex patterns of potential misuse and to track this back to identify review sellers and buyers," a Trustpilot spokesperson said.
"This has enabled us to launch legal action against companies that are buying fake reviews, and work with other social media platforms to remove review sellers."
Additionally, Trustpilot consumers now have the option to verify their identity on the site.