Forgery gangs plan to flood Glasgow with thousands of fake bank notes during next year's Commonwealth Games.
It is feared that the city’s retailers will be the main target of fraudsters using counterfeit bank notes during the 2014 sporting event.
Tens of thousands of sportsmen and women and athletics fans will descend on Glasgow next July and police are warning visitors and city shops to be vigilant.
While security will be tight at the sporting arenas, it is feared criminal opportunities are likely to present themselves in other areas.
Police said officers are "committed" to ensuring the safety of spectators and visitors during the 11 days of competition.
Chief Inspector Alan Porte, who is in charge of policing the city centre, said: "Given the numbers of visitors expected at the Games, Police Scotland will be doing all that we can to make sure that people come and enjoy all that Glasgow has to offer and remain safe.”
"Criminals are becoming ever more sophisticated in their ways of using technology to produce counterfeit currency. That said, we continue to be successful in tackling the issue. As a member of the public, the simplest way to protect yourself from this kind of crime is only to deal with people you know and trust.”
“If you need to receive cash from someone you don't know, ask them to accompany you to the bank, or even better, do your transaction electronically. If you are in doubt about the quality of a note, or if it doesn't feel right, don't accept it."
Police insist they are not aware of any influx of counterfeit currency in to the city centre but officers are urging both locals and visitors to be vigilant when they handle currency.
Fake cash leaves shops with the worthless currency and out of pocket after having given real cash back as change, as well as losing the items the con artists have "bought".
Last year, police launched an investigation after conmen targeted Glasgow shops with fake bank notes. The fraudsters bought items, including mobile phones and computers, with counterfeit Clydesdale Bank £20 notes.
It is feared the Commonwealth Games will only add to the problem as shop staff and sales desks are expected to be under "increased pressure" during the Games, making it more likely for fake notes to be accepted.
Mr Porte, said: "Businesses should be vigilant and use detection systems whenever possible. This will make it more difficult for criminals to pass counterfeit cash as genuine and therefore reduce the chances of such cash entering general circulation."