The Naval Service patrol ship LÉ Róisín is to set sail on Sunday on humanitarian rescue duty in the Mediterranean.
The ship under the command of Lieut Cmdr Ultan Finegan will have 60 officers and crew on board and will be stationed until mid-July, when it may be replaced.
It is the fourth Naval Service patrol ship to be deployed in the Mediterranean as part of a bilateral arrangement with Italy.
Minister for Defence Simon Coveney said that he believed Ireland should "continue to support Italy in a practical manner as far as possible and the Italian authorities have indicated that ongoing support is welcome".
The Defence Forces say that the agreement is focused solely on search and rescue, and is separate to the EU's Triton mission which is focused on border control .
Some 8,592 migrants were rescued last year by the LÉ Eithne, LÉ Niamh and LÉ Samuel Beckett, which Mr Coveney described as a “remarkable” effort.
Italy has rescued about 250,000 migrants at sea in the past three years, with 20,000 this year alone,
More than 700 migrants and refugees have died already this year attempting to cross into Europe via the Mediterranean, according to the International Organisation for Migration (IOM).
That is a 50 per cent increase on the same time period last year, when a total of some 3,770 migrants, including young children, lost their lives on what the organisation describes as the “deadliest” transit routes of all.
Most of the fatalities have occurred on the central and eastern Mediterranean routes, the IOM says.
The controversial EU-Turkey operation to return migrants from Greece to Turkey is expected to increase pressure on the southern Mediterranean, or so-called "central" migration route where the Naval Service will be stationed.
Italian ambassador to Ireland, Giovanni Adorni Braccesi Chiassi noted last month that numbers attempting to leave Libya were rising in spite of efforts to confiscate smugglers' vessels.
Mr Coveney said that any change in the focus of Ireland’s participation, such as through the EU Navfor Med military operation to stop traffickers, would require a debate in the Dáil as part of “triple lock” approval by the UN, EU and Government, and would therefore be a matter for a new administration.
Ireland also makes a financial contribution to the EU border control missions.
Last year, the head of the EU border agency Frontex Fabrice Leggeri said that saving migrants' lives in the Mediterranean should " not be the priority for the maritime patrols he is in charge of", despite the demand for a more humane response from Europe
The Immigrant Council of Ireland has welcomed deployment of another ship on rescue duty, but has said it is “equally important that political leadership is provided to ensure Ireland meets its other refugee commitments in full – including the promise to resettle 4,000 people by the end of next year”.
