A ring of steel will surround the Pope when he visits the Republic this weekend.
Tight security measures have been put in place around Dublin for Francis before he arrives for the World Meeting of Families festival.
Huge security barriers have been erected around Phoenix Park ahead of the Papal mass and other parts of Dublin where he will visit.
The security bill is likely to cost tens of millions of euros with the Dublin government and Catholic Church footing the bulk of the costs.
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The pontiff, who will be in the Republic for less than 48 hours, will stay at the Apostolic Nunciature of the Holy See in north west Dublin.
In May last year, Pope Francis appointed Archbishop Jude Thaddeus Okolo as the apostolic nuncio to Ireland, the first African priest to hold the role.
The apostolic nuncio is the papacy's diplomatic representative in Ireland.
It is understood that the high security bill will be lower than the last VIP visitors, the Queen and President Barack Obama.
Over €36 million was spent on the 2011 visits.
Thousands of Gardai, military personnel and members of the Defence Forces will be deployed around Dublin and Knock in Co Mayo when he visits the Knock Shrine on Sunday morning.
Gardai have been patrolling the Knock area since June after it was confirmed the pontiff would visit the pilgrimage site as part of his trip.
A number of road closures will be in place while the Pope's route through the city will continue to be searched and secured ahead of the visit.
Extra policing resources and overtime is expected to push up the Garda bill which is thought to be around five million euro.
The Garda's air support, the Defence Forces, Emergency Response Unit and the the Air Corps will be on standby as back up.
The Pope will make his way though Dublin city in his Popemobile, making him more visible to the large crowds.
