Small businesses are being warned about a scam in which firms are asked to pay to register domain names.
A number of firms have been "cold called" by registration agents who say "third parties" are interested in registering a similar name.
The businesses are told there is only a very short timescale to purchase it or they risk losing the name.
The Office of Fair Trading (OFT) said it had found a significant number of these claims could not be backed-up.
Businesses who have received calls and are concerned are advised to contact their local Trading Standards office.