Revenue has reminded shoppers that they should check whether the advertised price of goods includes all tax and duty costs when buying online from outside the EU in the run up to Christmas.
The tax collection agency said that where the price does not include these costs, additional charges may apply when the products arrive into Ireland from non-EU states, including the UK.
These include customs duty and VAT.
"Since January last, the United Kingdom is not a member of the European Union," said Maureen Dalton, Head of Revenue's South East Frontier Management Branch.
"This means that customs formalities and, in certain circumstances, additional charges now apply to goods bought from the UK, excluding Northern Ireland."
Ms Dalton also pointed out that since July, new rules mean goods arriving into Ireland from non-EU countries came are subject to VAT regardless of their value.
"In some instances, the supplier may operate a duty paid model, where the total advertised price for the goods at the time of purchase includes Irish VAT and duties meaning no further Revenue charges will arise on delivery," she said.
"However, where this is not the case, the amount of VAT and any duties due will be payable when the goods arrive in Ireland."
"You will have to pay these charges to the postal service or parcel operator before the goods are delivered."
However, the charges do not apply when goods are bought from within Ireland or the EU.
"Consumers also need to remember that, separate to import taxes and duties, it is normal practice for parcel operators to also charge an administration fee," Ms Dalton said.
"Administration fees can vary so should be checked by consumers before they make their purchase."