Complementary hotel stays and brand collaborations all carry tax and disclosure obligations and smaller creators are not exempt, they warned.
At an event hosted by the ASA, Revenue principal officer Justin Walsh said many influencers may be unknowingly breaching tax law by failing to declare gifted goods.
“There are no special exemptions for creators. If you receive something and promote it in any way, it falls under taxable income,” Mr Walsh said.
Revenue confirmed that gifted items not posted about online may still be liable for gift tax under capital acquisitions rules.
Gifts above €3,000 from any one donor in a year are taxable at 33pc, with a lifetime exemption limit of €20,000 for those in the Group C category – the threshold that typically applies to influencers receiving goods from brands, Revenue said.
“If you get something for free and don’t return it, you’ve received a gift and the gift tax rules apply,” Mr Walsh added.
Creators who earn any form of income from social media must register as self-employed, file annual tax returns and keep proper accounts on income, it said.
Vat registration is required once income from services exceeds €42,500. Mr Walsh noted that early compliance with these rules is advised.
“It’s always better to come to Revenue before Revenue comes to you.”
The warning comes as the ASA reports increasing public frustration with undisclosed advertising.
Chief executive of the ASA Orla Twomey said that Irish consumers do not like be to misled and are quick to report influencers who fail to label commercial content.
New ASA research shows growing awareness of advertising disclosures among social-media users.
Recognition of the label #ad has risen from 47pc in 2022 to 63pc this year, while 76pc of respondents believe online promotions should be regulated to the same standard as traditional media.
“Consumers want to know when they’re being advertised to,” Ms Twomey added.
The study found that more than half of Irish consumers now check influencer posts before shopping, with TikTok being the app that users check the most for posts that include advertising.
In August, the ASA signed a data-sharing agreement with the Competition and Consumer Protection Commission (CCPC) allowing both agencies to exchange details of repeat offenders.
Complaints upheld by the ASA are published online and remain searchable by name.