Asked about the motion on Friday, Polanski said: “If your Zionism is the displacement of the Palestinian people then that is clearly racist, and I say that as a Jewish leader of a British political party.”
However, he said he wanted to see the reference to a single Palestinian state changed, arguing: “I don’t believe we as a Green Party of England and Wales, or even the British government, should be deciding what the future settlement looks like.”
He had also said he wanted to see the motion amended to specify that it should not be used to discipline Jewish members attending synagogues that consider themselves Zionist.
However, both amendments favoured by Polanski were rejected by Green members.
A Green spokeswoman insisted the party would protect Jewish members – and they would not be persecuted for attending synagogues which defined themselves as Zionist.
Speaking after the motion had been approved, chair of Jewish Greens Vivien Lichtenstein told the BBC she could consider her future in the party.
Polanski has not specified whether he supports the motion passed by members, but added his name to a joint statement from the party’s five MPs and deputy leaders issued after the vote.
The statement pledged to ensure the Green Party was “an anti-racist party in every way” and added that there was “no conflict between supporting the rights of Palestinians and the rights of Jewish people”.
Over the course of the three-day conference, the key figures in the party have expressed differing positions about the Zionism motion.
Four of the party’s five MPs – Ellie Chowns, Adrian Ramsay and Carla Denyer, Sian Berry – had publicly opposed it, with Denyer arguing it could risk “alienating a significant proportion of Jewish people”.
Chowns, as well as former Green Party leader Caroline Lucas, both spoke against the motion during the debate.
Addressing members, Lucas said: “I urge you not to support the over-simplification at the heart of this motion – a refusal to accept complexities which is leading to so many Jewish members feeling scared and unwelcome in our party.”
Deputy leader Mothin Ali, who had expressed support for the motion before the vote, said it was calling for “a state that’s democratic, that guarantees the rights of every single person living on that land”.
He added that he was “absolutely not” calling all Jewish people who define themselves as Zionists racist.
Following the vote, Israel’s Foreign Ministry said the motion went beyond “the boundaries of legitimate political debate” and was “a stain on the history of the United Kingdom”.
Under Green Party rules, motions supported by members become official party policy, but will not necessarily be included in the party’s manifesto at the next general election.