Revenue is warning shoppers that they may find themselves liable to pay significant tax and duty bills for products bought online.

Last year Revenue officers applied charges averaging €28.70 to more than 76,000 packages at postal depots around the country. 

As internet traffic builds and bargains are offered in the lead-up to the Black Friday and Cyber Monday peak pre-Christmas shopping events, Revenue is advising consumers to watch out for prices for popular goods that seem especially low. "This may be because tax and duty has not been accounted for," it said. "However, once your goods arrive in the State, you are liable for the additional charges and non-payment can result in your goods being seized".

Almost all goods arriving from countries outside the EU and European free trade area will be liable to tax and duty. Goods witha customs value of more than €22 are liable for VAT and goods that cost more than €150  - including transport, insurance and handling charges - incur customs duty and VAT liabilities.

In one example cited by Revenue a "branded mobile phone" bought online from the US would cost up to €250 in customs duty, insurance, VAT and handling fees.

Revenue also seized counterfeit goods worth €7.8m last year. "Fake handbags, runners, and phones are widely sold online, are among the counterfeit goods most commonly seized by Revenue and, because they are not subject to regulation, may pose health and safety dangers," it said.