The Competition and Consumer Protection Commission has issued a warning that consumers are being targeted by "increasingly sophisticated online scams".
The warning comes as Black Friday and Cyber Monday sales kick off the busiest shopping period of the year.
With recent CCPC research revealing that around one in four people expect to make a purchase in the sales, the watchdog is advising consumers to be extra vigilant.
It said shoppers should be "especially wary of ads on social media, as scammers are using convincing clones of trusted websites and fake local shops to trick shoppers".
Consumers are also advised to always purchase through retailers' official websites or apps rather than clicking on links on social media ads.
To highlight the dangers posed by different types of scams, the CCPC has published case studies of real life scam tactics that have been used on people who contacted the watchdog afterwards.
The case studies date from November 2024 to last August and reveal losses ranging from €42 to €20,000.
In one case, a consumer paid €125 by debit card for an armchair after clicking through an ad on a social media platform to what he thought was the website of a furniture retailer.
However, when the furniture did not arrive a few days later, he contacted the actual retailer and was told there was no record of his order.
The man realised he had bought from a cloned website and, after receiving no help from the social media platform, he then contacted the CCPC, his bank and reported the scam to gardaí.
His bank reversed the debit card transaction and he recovered the full €125.
Another incident involved someone who ordered a shoulder brace online, paying €30 by debit card, before realising the transaction was a scam about five days later when the brace had not arrived.
The same business took a further €46.15 from his bank account, which was reversed by the bank.
The consumer said that "on reflection" the website and photos "didn’t look quite right".
He also found online reviews from others who had the same experience and said he would have known the offer was a scam if he had checked the reviews first.
Director of communications at the CCPC Gráinne Griffin said online scams "have become more and more sophisticated, using convincing images and stories and carefully tailoring their ads to seem like they’re a trustworthy business".
"It’s important that consumers avoid rushing into online purchases and transactions," she said.
Ms Griffin urged consumers to take care when shopping online "for the sake of your finances and your safety".
"Don’t let tactics like time sensitive offers or countdown clocks pressure you into making a decision you might regret," she added.
The CCPC said anyone who thinks they have been scammed should contact their bank/payment provider immediately, as they may be able to initiate a chargeback and get money back.
