Pubs are being urged to double-check that they do not have any gaming machines that are operated illegally after a series of police seizures.
The Gambling Commission seized evidence from nine licensed premises on 24 May in an operation that involved four police forces.
It follows a national police operation focusing on the illegal manufacture and supply of gaming machines.
The concerns focuses on Amusements With Prizes (AWPs) being presented as Skills with Prizes (SWPs) machines in an alleged bid to pay less tax.
British Beer & Pub Association chief executive Brigid Simmonds said: "Pubs need to be aware, so they are not caught out, as the Gambling Commission is determined to see these new rules enforced.
"It is possible that some of these machines have inadvertently found their way into pub premises, so pubs do need to double-check, to protect themselves."
Nick Arron of Poppleston Allen licensing solicitors said: "To ensure you are compliant and do not fall victim to the illegal supply of machines, check your supplier's operating licence.
"It should be a Non Remote Gaming Machine Technical Supplier or a Non Remote Gaming Machine Technical Full licence.
"It would also be an appropriate time to check the permissions you have.
"Alcohol licensed premises should have notified the council that they will be operating one or two gaming machines or have applied for and been granted a Licensed Premises Gaming Machine Permit. The permit will state the number and category of machines, which in a pub is category C or D."