Dozens of residents in the county have received suspicious letters part of an inheritance scam, Lincolnshire Trading Standards said.
Trading Standards officials were notified of almost 20 incidents in just two days.
They are urging people to be on the lookout for letters from China telling them that they have been left large amounts of money and shares by a long-lost relative.
To release the inheritance, the unsuspecting victim is asked to carry out some instructions, which include paying an upfront fee or calling a premium-rate number.
The value of the inheritance varies but has been as much as £16 million, and Trading Standards are concerned that more people could receive the letter and that some may believe it.
Mark Keal from Lincolnshire Trading Standards said: “These fraudsters are relying on people being taken in by the exciting thought of coming into some money.
“The intention is to persuade someone to send cash on the promise of a larger return. But no genuine organisation would ask you to do that.
“In many ways, this is an obvious scam. But it will only take one trusting person to make it worthwhile for the fraudsters. If you receive the letter, please just throw it away.”
Anyone who believes that they have been the victim of a scam and would like advice can contact Lincolnshire Trading Standards on 01522 782341 or via email.