Victims of scams are having their details included on a "suckers list" which is then sold on to other fraudsters, according to the National Consumer Agency.
The agency announced details of a scams awareness campaign, to start next month, which will aim to help consumers protect themselves from con artists.
"It is believed that some consumers are specifically targeted again and again by scammers on the principle that they were naive enough to have been caught once and are liable to be caught again," said chairwoman Ann Fitzgerald.
The agency was aware of a case in which an 85-year-old Australian who forwarded a sum of money to a Canadian company who had told him he could claim an inheritance. "Unfortunately, it has come to our attention that he fell for the same story, this time from an Irish company, but again there was no pot of gold waiting for him to claim."
As well as English and Irish, the campaign will be run in Latvian, Lithuanian, Mandarin, Polish, Portuguese, Romanian, Hungarian, Czech and Russian in an effort to reach minority groups.
Although there are no statistics for Ireland, British research suggests that 59 per cent of adults there had been the victim of a scam, costing up to €1.5 billion annually, Ms Fitzgerald said.
"Scammers have many ways of targeting people in Ireland including phone calls, e-mail, post and door-to-door visits. The most common scams are often disguised as special promotions, prizes or free holiday offers.
"All of these scams have the common thread that they seek to persuade the individual targeted to part with money or with sensitive financial information."
She added: "Very often people who have been victims of scams do not report them, perhaps because they don't want to look foolish or they may not be sure that it was actually a scam. The reality is that scams are not targeted only at the weak and vulnerable. Be aware there is a scam out there with your name on it and that we all need to be vigilant."
The anti-scamming campaign starts on April 1st.
Scams and shemes: some common practices
WINNING PRIZE:A nurse coming back from India gave her name and address in response to a questionnaire. She then received a notice saying she had won a substantial sum and needed to forward a small sum to clear the paperwork and revenue taxes. The certificates she received from the "Spanish Authorities" were authentic-looking but she handed out over €13,000 before realising she had been scammed.
SECOND-HAND CAR:Having advertised his car in a magazine, a consumer was approached by a dealer who claimed he had clients who were interested in buying it. He offered to pass on the car-owner's details to them for a nominal fee. The cash was handed over but no list of purchasers ever emerged.
LEGACIES:A company advertising in several countries says it has details of unclaimed legacies in Ireland and offers to keep customers informed of these for a fee. All that those who paid up received was a badly composed newsletter.
DIRECTORY ENTRY:In this perennial scam, a false invoice is posted to a company for an entry in a spurious directory. The initial demand for payment is followed up by more insistent demands and threats to begin legal proceedings.