"The lack of concern that we see in many countries for the suffering and exploitation of such desperate people is deeply shocking," he said, at the start of a major conference on migration in Geneva.
He added: "Rich countries must not become gated communities, their people averting their eyes from the bloodstains in the driveway."
To the anger of campaign groups the British Government has said it will not support future search and rescue operations beyond supplying a technical expert to Triton, claiming such missions simply encourage more migrants to make the journey.
Migrants in a boat during an Italian navy rescue operation off the coast of Sicily. Photo / AFP
Britain's position was echoed yesterday by Matteo Salvini, the head of Italy's right-wing Northern League party, which has surged in the polls on its anti-immigration ticket.
"The 3419 deaths in the Mediterranean are on the conscience of those who wanted operation Mare Nostrum," said Mr Salvini at the Foreign Press Association in Rome.
But Antonio Guterres, the UN High Commissioner for Refugees, dismissed this argument.
"If entire families are risking their lives at sea today, it's because they have already lost everything else and see no other option to find safety," he said.
Record number of migrants
All told, a record 348,000 migrants and refugees attempted risky sea crossings this year in search of a better life in Europe, Southeast Asia, the Caribbean and the Middle East, 4272 of them dying in the process, according to the UN refugee agency.
Most of those crossing the Mediterranean headed to Italy first, and the country has rescued more than 150,000 people so far this year.
Italy set up its Mare Nostrum rescue mission in 2013 to reduce the death toll, following two migrant disasters in October that year.
Mare Nostrum officially ends on 31 December, although the Italian navy has indicated it intends to continue rescue missions.
Meanwhile, the exodus from Africa and Asia continues. A total of 408 migrants, mainly Syrians, have been rescued after spending six days adrift on a boat in the Mediterranean, Spanish officials said.
The migrant craft was intercepted by a Spanish oceanographic vessel on Tuesday about 150 nautical miles east of the Sicilian port of Augusta.
- Independent