Some 593 people have been rescued from six vessels off the Libyan coast by the Irish ship LÉ Eithne.
The Defence Forces said the rescue operations commenced at 4am Irish time when 101 migrants were taken from a rubber craft 50 nautical miles northwest of Tripoli.
It quickly proceeded to five more consecutive rescue operations, which were completed at 1pm on Sunday.
There were 496 men, 92 women and five children rescued and taken safely on board the ship, according to provisional figures.
A Defence Forces spokesman said the vessel was now awaiting direction from the Italian Maritime Rescue Co-Ordination Centre for its next tasking.
Eithne departed Naval Service headquarters in Haulbowline, Cork, on May 16th to assist the Italian authorities in the humanitarian search and rescue operations in the Mediterranean. Search and rescue operations began on May 28th.
The crew on the Irish ship has now rescued more than 2,700 people.
A Naval Service vessel will be deployed in the Mediterranean for a period of up to six months over the summer.
Earlier this month, vessels from Germany, Britain, Italy and other countries took on board some 3,000 people who had been crammed on to just five small boats in the Mediterranean.