Zack Polanski has said he will not accept anyone being excluded from the Green Party “because of the religious or communal body they are part of”, after members adopted a motion declaring Zionism a form of racism.

The Green leader said “no-one will be made unwelcome because of their background, their faith, or where they worship”.

The motion defines Zionism as an ideology supporting “an ethnonationalist Jewish state” and backs a “single democratic Palestinian state in all of historic Palestine”.

He added: “As leader I will not accept any exclusion, or refusal to engage with anyone, because of the religious or communal body they are part of.”

The motion has exposed divisions between the party’s newly enlarged membership base under leader Zack Polanski and its MPs elected at the last general election.

Polanski did not take part in the vote on Sunday and four of the party’s five MPs opposed it.