Bailiwick Law Enforcement believes the men to be Irish and without correct licences to work in the island.
They have been offering services such as driveway cleaning, roofing work or gutter cleaning.
“It is believed they were driving a Toyota Proace City Active Grey panel Van,” said BLE on Facebook.
“Generally speaking, people should always be careful of cold callers who offer to make building repairs, tarmac your drive, clean and repair gutters etc.
“Often, they will ask for money in advance, they my even offer to drive you to the bank to withdraw money to pay them.
“Typically they seek to exploit the vulnerable and elderly members of our community and will use tactics such as intimidation and exploitation of the good will of those they target.
“While this is not a regular occurrence in Guernsey and we do not want to unnecessarily cause alarm, there are those who on occasion are willing to travel to Guernsey to exploit our community and we need to be aware of the harm and damage they can cause.”
Bailiwick Law Enforcement has published the following advice:
