The multitude of migration crises facing the world are symptoms of a long line of brutal conflicts and rights violations, the UN rights chief said yesterday.

"Political turbulence, repression, violence and war have become so widespread that they impel many millions of the world's people to risk their lives to find a place of relative safety," said Zeid Ra'ad Al Hussein.

"Migration is the symptom, the cause is despair, after repeated human rights violations have stripped an individual of all hope of justice and dignity," he told the opening of the UN Human Rights Council's June session.

More than 100,000 people have made the perilous journey across the Mediterranean to Europe so far this year, and some 1,800 have drowned trying. Southeast Asia's migrant crisis meanwhile unfurled at the start of May, leaving thousands from Bangladesh and Myanmar's persecuted Rohingya minority trapped at sea.