Last summer's high profile garda operation aimed at illegal immigrants which led to the detention of 140 people cost the State €101,518, almost half of which was in overtime payments.
Some 600 gardaí were involved in Operation Hyphen in July which led to 15 unsuccessful asylum-seekers being deported.
Gardaí visited some 294 premises in the operation, the first of its kind, which has been criticised by immigrant support groups and opposition politicians as being costly and counter-productive.
A total of 74 people were charged with immigration-related offences and one sought asylum. Fifty people were released with out charge after they proved they were legally resident in the State.
The total money spent on the operation, including overtime, was €30,226 in the Dublin Metropolitan Area, €49,723 outside Dublin and €21,569 for the Garda National Immigration Bureau, which took a lead role in the initiative.
Gardaí worked a total of 1,768 overtime hours on the two days of Operation Hyphen - July 16th and 23rd. This total included 690 hours in the Dublin Metropolitan Area, at a cost of €18,465. Gardaí outside Dublin worked 674 hours, at a cost of €18,036. Members of the Garda National Immigration Bureau worked 404 hours of overtime, costing €10,811.
The cost of the operation was revealed by the Minister for Justice, Mr McDowell, in response to a recent Dáil question from Mr Finian McGrath TD, for Dublin North Central.
In a letter to Mr McGrath, the Minister said it had not been possible with the time available to obtain the details of the cost of the operation when the parliamentary question was tabled in October.
Mr McGrath said last night he was "absolutely hopping mad" when he saw the amount of tax payers' money spent on an operation which had led to the deportation of only 15 people.
"In parts of my constituency where there are attacks on elderly and anti-social crime the guards always complain that they don't have resources on the ground to deal with these issues," he said.
Mr McGrath said Mr McDowell, was spending €101,000 when we have "thousands of Irish people in America and many of them are illegal. If this happened against the Irish in America, he and I both would be the first people getting onto the American authorities about hassling Irish immigrants."