The rabbinical leader of the haredi Orthodox Agudath Israel of America said the Conservative and Reform movements “will be relegated to the dustbins of Jewish history.”

Rabbi Yaakov Perlow, the Novominsker rebbe, also slammed a more liberal branch of Orthodoxy at Agudah’s annual dinner Tuesday in Manhattan.

Perlow, the head of Agudah’s Council of Torah Sages, said the Reform and Conservative movements “have disintegrated themselves, become oblivious, fallen into an abyss of intermarriage and assimilation.”

The Open Orthodoxy movement led by Rabbi Avi Weiss, which seeks a greater role for women in Jewish ritual, is “heretical,” Perlow said. He also called on Modern Orthodoxy to “stand up and reject these new deviationists cloaking themselves in the mantle of Orthodoxy,” the Forward reported.

The remarks were first reported Wednesday by the Forward.

New York Mayor Bill de Blasio appeared immediately after Perlow and praised Agudah and the ultra-Orthodox community for its growth.

De Blasio said his universal prekindergarten program was designed for the Orthodox Jewish community.

“From the very beginning, I knew this would succeed for all of New York City if it was also something that succeeded for this community,” de Blasio said. “The yeshivot were such a crucial part of it. I knew if we did that so many children would benefit.”