The reduced VAT rate for tourism, hospitality, and some other services returned to 13.5 per cent at midnight.
The 9% rate for tourism, hospitality, pubs, and hairdressers have been impacted as a result.
It means Ireland will now have the third highest hospitality VAT rate in Europe.
The Restaurant Association of Ireland said the move by the Government to increase the 9% VAT rate will result in thousands of job losses in the sector.
Aisling Kelly, who owns Sligo Oyster Experience, described the decision as "madness".
“I think it’s madness, to be honest.
"Because even the Government will see my Revenue returns, how businesses are doing, and they’re blaming a few hotels that are doing well and basing it on the rest of the country.
"It's just wrong."
Excise Duty
As of midnight last night, motorists will also have to fork out more for fuel.
The price of petrol has gone up by 7 cent a litre and diesel has risen by 5 cent.
Farmers are also being hit, with the cost of agri-diesel increasing by one cent per litre.
By James Cox
