More than 400 migrants, mostly from Somalia, are reported to have drowned in the Mediterranean Sea on a boat trip from Libya to Italy.
The disaster came on the first anniversary of the Lampedusa tragedy in which some 800 died.
The charity Oxfam Ireland has called on the acting minister for defence to re-deploy Irish Navy vessels to the Mediterranean.
Oxfam is calling on Irish and European governments to immediately ensure safe and legal passage for all those travelling to Europe.
Somalia's state radio quoted the Somali Embassy in Egypt in reporting the incident.
In a joint statement from the president, prime minister and speaker of parliament in Somalia, they said 400 migrants had drowned in the capsizing.
But later the Somali information minister said there was confusion over the number of casualties, which could be 200.
"It's a painful tragedy which reminds us all how important it is for us to discourage our youth from embarking on such high risk journeys," the statement said.
A Somali news website, Goobjoog News, carried an interview with Awale Warsame, who said survived the incident.
"There were 500 passengers, mostly Somalis on the boat, but only 23 people survived," he said.
"Survivors, including me, had to use broken wood pieces from the capsized boat to float over waters before we were rescued.
"We had travelled from Egypt, especially Alexandria, on April 7th and the boat capsized on April 12 but we were rescued by a Filipino ship off a Greek island five days later."
Egyptian Foreign Ministry Spokesman Ahmed Abu Zeid said his office had no information and officials are checking the reports.
The Greek coast guard said it had no report of a boat sinking in the area.