The European Commission is referring Ireland to the European Court of Justice (ECJ) for failing to implement EU rules on package travel.
The rules are designed to ensure agencies offering package holidays give clear information.
This is particularly an issue on the full cost and any additional charges.
In 2015, EU member states agreed to give legal footing to a range of enhanced protections for consumers.
This included stronger cancellation rights, clearer rules on liability, refunds and repatriation in case organisers go bankrupt.
The European Commission office in Dublin has said the case is being referred to the ECJ because the Government has still not fulfilled its obligations to protect tourists.
The commission will call on the court to impose the payment of the lump sum based on a daily amount of €3,808.80, with the minimum lump sum of €1,181,000 and a daily penalty of €15.996,96.
The penalties are calculated taking into account the "seriousness and the duration of the infringement", as well as a member state's capacity to pay and its institutional weight.
Commissioner for Consumers, Vera Jourová, said: "The EU package travel directive brings great benefits for consumers and businesses alike.
"The rules are adapted to the digital age and the new ways of booking holidays.
"Travellers also benefit from new rights and be well protected in case the operator goes bankrupt.
"The new rules make it easier for travel businesses to offer their services cross-border.
"We urge Ireland to transpose the directive as promptly as possible to avoid unnecessary fines."
Member states had agreed to enter the rules into national law by January 1st 2018, and for them to enter into force on July 1st that year.
In March last year, the commission opened infringement proceedings by sending a letter of formal notice to Ireland - followed by a reasoned opinion in November.
It said Ireland has still not notified the full transposition of the directive into national law.
Main image: A hearing of the European Court of Justice by five judges | Image: ECJ