Irish taxpayers will have to pick up a 3.6 million euro (£3 million) bill for policing the G8 summit.
Around 900 Garda officers were tasked to a massive operation along the southern side of the border last June as world leaders met in Co Fermanagh.
Despite warnings of both home-grown and overseas security and terrorist threats, demonstrations were relatively small and largely peaceful.
In the Irish Republic, Garda chiefs mounted Operation Shield to counter any attacks or disruption at the gathering of the leaders of the world's richest economies.
Figures obtained by the Press Association and branded "simply outrageous" show Garda costs for the operation running to at least 3.64 million euro (£3 million), as of the end of August.
However, the bill has come in under budget because the event was so low-key. "It was certainly less than what was anticipated," said one Garda source.
Most of the costs relate to Garda wages, overtime and subsistence, as hundreds of extra officers were billeted to the border counties of Donegal, Leitrim, Monaghan, Cavan and Louth.
A temporary headquarters was set up in Ballyconnell, Co Cavan.
There were also bills for upgrading radio systems to allow for better communications between the PSNI and the Garda, as well as the purchasing of some security barriers and infrastructure.
Travel costs during the planning stages leading up to the operation are among the overall total.
There were no arrests or disorder related to the G8 summit south of the border.
The costs for the policing operation have been sent to the Department of Justice, and will not be taken from the Garda budget.
Three months after the summit, Justice Minster Alan Shatter's department said it still does not have a breakdown of the costs.
But it said the 3.64 million euro (£3 million) bill accounts for "most of the relevant Garda expenditure", although the figure may climb higher as more claims come through.
Socialist Party TD Joe Higgins said the bill was outrageous at a time when the Government was savagely slashing allowances towards home help carers and the disabled.
"The fact that it wasn't even in the jurisdiction and spending that amount of money is simply outrageous - against the backdrop of cuts to public services," he said.
Mr Higgins said not only were the G8 leaders presiding over disastrous austerity policies internationally but they are "paranoid" over the hardship they are imposing.
"The ordinary people have to pay for their protection," he said.
In July, the Stormont Executive revealed the G8 summit cost the UK public purse around £75 million (89 million euro) for policing and security alone.
Approximately 8,000 police officers, many drafted in from Britain, were on duty during the two-day gathering of world leaders at the Lough Erne resort.
A spokesman for Minister Shatter admitted the costs were "undoubtedly significant" but said they were appropriate.
"The G8 Summit was a very high profile event of which security was a major element," he said.
"In that context a wide range of Garda measures had to be put in place, on the basis of assessments carried out by the Garda authorities, and they had to take particular account of the fact that a number of the delegations attending the summit were based within the jurisdiction.
"Overall, while the costs figure is undoubtedly significant, the minister considers that the relevant security provided was appropriate and that the arrangements made by An Garda Siochana in respect of the summit were very successful."