A number of imitation Love2Shop gift vouchers are in circulation across the country and in North Yorkshire, police said.
These vouchers are often used as part of employee rewards programmes or to save up for Christmas presents.
The vouchers look very realistic but there are three simple ways to check if they are genuine, police confirmed.
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The warning signs are:
The security seal should peel off, on a fake voucher it will tear off
Underneath the security seal there should be circles and symbols
The hole punched out of the voucher should be slightly irregular in shape, with feathered edges - not a perfect circle.
North Yorkshire Police said: "Never purchase these vouchers from online selling sites such as Facebook Marketplace or Gumtree, only buy them from registered retailers or from the Love2Shop website.
"If you think you have purchased fraudulent vouchers email: [email protected]
"Or if you work in a retailer where someone has tried to pay using fake vouchers, please call us on 101."