Irish authorities are to evacuate 1,000 civilians by chartered ship from the besieged Libyan city of Misrata.
Humanitarian group the International Organisation for Migration (IOM) will arrange the emergency mission from the city, which has been under intense fire by forces loyal to Libyan leader Muammar Gaddafi for almost eight weeks.
Irish Aid is putting up 300,000 euro to fund the mission and another 200,000 euro to support the evacuees when the boat arrives at the rebel stronghold of Benghazi.
Tanaiste and Foreign Affairs Minister Eamon Gilmore said the Government felt a responsibility to act.
He added: "Gaddafi's forces have agreed to allow ships into the port to evacuate civilians and we have requested that the IOM undertake an emergency operation on our behalf. Irish Aid officials have been in close contact with them over the last few days, putting in place the necessary measures for the mission to take place."
Libya's third largest city, the only rebel stronghold in the west of the country, has been under siege by forces loyal to Gaddafi for almost eight weeks. The United Nations (UN) last week estimated that at least 20 children have been killed in the hostilities.
The IOM has already carried out three rescue missions, funded by Britain, Germany and the European Commission (EC), but it is not yet known when the latest attempt will take place. The 500,000 euro sum brings total Irish support for the IoM operation on Libya's border to one million euro.
Amnesty International Ireland said the Government deserves immense credit for its decision to evacuate the civilians.
Colm O'Gorman, executive director, said: "The people of Misrata are now in the middle of a full-fledged humanitarian crisis. Earlier this week Amnesty International called on the international community, including Ireland, to act to protect the civilian population.
"With civilian casualties in Misrata mounting day by day, the decision announced today will help save lives and the Government deserves immense credit for its actions."