Blackpool Police say they have received several calls about rogue traders in the town in the last two days.
And officers are warning residents to be vigilant about cold callers offering to do repair work on people's homes.
A police spokesman said:"Rogue traders who cold-call are deceiving consumers, particularly the elderly and vulnerable, offering to carry out property repairs such as, roofing work, clearing of guttering and fascia or soffit repairs.
"Doorstep crime can affect anyone however, because rogue traders often prey on the most vulnerable in society.
"The work carried out is often substandard and overpriced, including unnecessary repairs, the deliberate damage of property in order to acquire work, claims that work has been completed which has not been done and false declarations being made about the membership of trade associations and experience/ qualifications of the offenders.
"The doorstep callers may use intimidating or aggressive tactics in order to frighten the person into contracting for services and parting with their money. "Alternatively, the callers may befriend the vulnerable victim to facilitate the crime, which often results in repeat offending."
Police say residents in the area can help raise awareness by talking to friends and relatives about doorstep crime in order to empower them and reduce their chances of becoming victims.
They are advising people to take the following tips:
•Never agree to work that is instigated as a result of a cold-call or leaflet drop
•Consider whether the work is necessary or wanted. If so, obtain at least three written quotes from reputable businesses or traders who are members of the Blackpool Council Safe and Secure Scheme
•Report an unwanted caller to trading standards on (01253) 478375