The Secretary-General's remarks came at an informal meeting of the UN General Assembly to address "concerns of a rise in anti-Semitic violence worldwide."
Ban, who is in Davos, Switzerland, to attend the World Economic Forum, addressed the meeting via video message, voicing support in the worldwide fight against anti-Semitism, which he described as "one of the oldest forms of prejudice known to humankind."
"Our efforts to build a world of mutual understanding are being severely tested today by rising extremism and barbaric acts," he said. "The poison of hatred is loose in too many places. Jews remain targets, as do Muslims and so many others."
The Secretary-General said grievances about Israeli actions must never be used as an excuse to attack Jews, and criticisms of Israeli actions should not be summarily dismissed as anti-Semitism.
"Our responses must avoid perpetuating the cycles of demonization and playing into the hands of those who seek to divide," he said.
Speaking at the meeting, German Minister of State for Europe Michael Roth said the world was witnessing a new wave of anti-Semitism.
"We are deeply alarmed by the increasing number of attacks against Jewish facilities and by the use of anti-Semitic slogans in demonstrations in many countries, including Germany," he said.
In Washington, President Barack Obama said that anti-Semitic attacks like those that killed four at a Paris kosher supermarket Jan. 9 “threaten the values we hold dear -- pluralism, diversity, and the freedoms of religion and expression.”
“When the human rights and fundamental freedoms of Jews are repressed, the rights and freedoms of other minorities and other sectors are often not far behind. For all these reasons, combating anti-Semitism is an essential responsibility for all of us,” he said.