Age Concern is asking the elderly to be careful when it comes to dealing with door-to-door salespeople.

The advocacy group has become aware of a number of instances where cold callers have taken advantage of elderly residents in the Nelson area.

Nelson Age Concern manager Sue Tilby is urging residents who feel targeted to make contact.

"We have a great relationship with the police where they will either let us know or we'll let them know something that we're concerned about."