ADS on social media for cheap products claiming to be popular brand names "often turn out to be fake and of poor quality or unsafe", Trading Standards have warned.
The Department for the Economy's Trading Standards Service is urging consumers to know their rights and avoid being a victim this Christmas.
Between the £100 Spend Local card and online buying, hundreds of millions of pounds are expected to be spent.
The department's Consumerline regularly receives an increase in complaints from consumers about faulty, misdescribed, or counterfeit goods, particularly goods that have been bought online, as well as delays with delivery or goods not arriving at all.
Chief inspector Damien Doherty said: "With fraudsters likely to make the most of the festive season by coming up with ever more ways to target consumers during the Christmas rush, we are urging shoppers to be vigilant and know their rights before parting with their money."
Consumerline can be contacted on 0300 1236262 and www.nidirect.gov.uk/information-and-services/government-citizens-and-rights/consumer-advice.
