Garda immigration officers spend thousands of euro every week on luxury business-class flights while returning home from deporting illegal immigrants from the country.
The Department of Justice, which released details of the flights under freedom of information, said business-class fares are booked while repatriating deportees where it is deemed a security risk for a garda to leave an airport.
These flight tickets for the return leg of journeys allow Garda National Immigration Bureau (GNIB) officers to stay in the airport lounge in the country where they are leaving the deportee, the department says.
Of the dozens of business-class trips after chaperoning illegal immigrants to their return destinations last year, several were to cities in Europe, including flights to Frankfurt listed as costing €19,600 and separately €3,800.
There were also fares to Amsterdam reaching €11,000, €7,300 and €4,400.
The Department of Justice said the Frankfurt flight costing €19,600 covered four GNIB officers travelling back from Lagos, Nigeria's largest city. The €11,000 and €7,300 flights to Amsterdam were also return trips from Lagos, and covered three officers.
Records show there were also business-class flights to Abu Dhabi costing €6,000 and frequent business-class flights to Istanbul totalling tens of thousands of euro.
A department spokesman said the Abu Dhabi flight was from Lahore in Pakistan and covered two GNIB officers.
"Istanbul appears so much because it is a major hub for returns from many South East Asian and Middle Eastern destinations," he said.
GNIB officers usually travel in pairs when chaperoning a deportee back to a return country, and sometimes more if it is deemed necessary under particular security circumstances.
Last year, GNIB officers ran up bills of €164,865 for business-class flights - averaging almost €14,000 a month, or more than €3,000 every week.
Almost 50 flights during 2018 were listed as business or first class, although 13 of these were cancelled and one was misclassified, according to the Department of Justice.
A spokesman said the vast majority of flights by GNIB officers are economy class.
"All 36 business-class flights relate to situations where GNIB officers are accompanying people being removed from the State on foot of deportation orders," he said.
"Business-class flights are booked where it is considered by An Garda Síochána that it would be a security risk for Irish officers to leave the airport in the destination country and to stay overnight in a hotel.
"By booking business class flights, the officers can stay in the airline's lounge until a return flight leaves to one of the European hubs. An economy-class flight is then booked from the European hub back to Dublin.
"We understand that many EU member states apply the same practice for their officers on return operations."
The spokesman added the State can recoup 75pc of the cost of the flights from the EU Asylum, Migration and Integration Fund (AMIF).
There were 860 "repatriation" flights last year. Destinations included Albania, Algeria, Bangladesh, Brazil, China, Egypt, Malawi, Malaysia, Mauritius, Mongolia, Nepal, Panama, Qatar, South Africa, Trinidad and Tobago, United Arab Emirates and Zimbabwe.