The founder of the doveish Israel advocacy group J Street and the disgraced former governor of New York are among the signatories to a statement defending Occupy Wall Street from accusations that it is antisemitic.

Last month the conservative Emergency Committee for Israel highlighted what it claimed were incidents of antisemitism and anti-Israel activity at the protest. It revealed footage of a protester complaining of a "conspiracy in this country where Jews control the media, finances" and images of demonstrators wielding signs reading "Hitler's Bankers" and "Gaza supports the occupation of Wall Street".

But the protest, now in its sixth week, has also attracted Jewish supporters, with a Kol Nidre service arranged at the site on Yom Kippur and a succah constructed at the camp a week later.

A group of 15 liberal Jewish activists have now released a statement criticising those who attempted to "smear that movement with false charges of antisemitism".

"We are publicly engaged American Jews who support both Israel and the ideas behind Occupy Wall Street," they said, pointing out that "a handful of hateful people…with offensive signs" should not be used to discredit the whole protest.

"It's an old, discredited tactic: find a couple of unrepresentative people in a large movement and then conflate the oddity with the cause.

"It is disingenuous to raise the canard about Jews and Wall Street in order to denounce it."

Eliot Spitzer, who resigned as g overnor of New York in 2008 after a sex scandal involving a $1,000-an-hour call girl, was one of those who backed the statement. Other supporters included J Street director Jeremy Ben-Ami and the rabbis in charge of the liberal organisations Progressive Faith Foundation and Rabbis for Human Rights – North America.