Zack Polanski has denied Israel has a 'right to exist' - after insisting Palestine is 'on the ballot' at local elections.
The Green leader merely said he did not believe 'any country' had a right to exist when he was grilled on the legitimacy of the state.
The comment, in an interview with ITV's Peston programme, came as Mr Polanski - who is Jewish - tries to quell concerns about anti-Semitism in his party.
Yesterday the London assembly member doubled down on criticism of way the police detained the Golders Green stabbings suspect last week, saying he had been 'traumatised' by the footage.
He also said Palestine is 'one of the things' on the ballot paper for the local elections – despite being 2,000 miles from the UK and not the responsibility of English councils.
The Greens are expecting to make big gains from Labour in the local elections, particularly in the capital.
Zack Polanski said he did not believe 'any country' had a right to exist when he was grilled on the legitimacy of the state of Israel
Asked on Peston about alleged anti-Semitic remarks by some council candidates, Mr Polanski said such abuse was 'unacceptable'.
However, he accused opponents of trying to 'score points', arguing it is possible to be a 'proud' pro-Palestine voice without straying into anti-Semitism.
'As I've said, we need to make sure that we have a standardised vetting process in the future,' he said.
Mr Polanski was asked about describing himself as a 'non-Zionist' Jew.
'It's ultimately recognising that I want to see equality for the Palestinian people, that there's been a genocide for the last couple of years that our government have been arming and sharing intelligence,' he said.
'I want to see an end to that genocide. And I want to see equality of voices at the table in making sure that we're building peace.'
Pressed on whether he thought Israel had a 'right to exist', Mr Polanski said: 'I don't believe any country has a right to exist. People have a right to exist.
Yesterday the London assembly member doubled down on criticism of way the police detained the Golders Green stabbings suspect last week, saying he had been 'traumatised' by the footage
'The Israelis have a right to exist. The Palestinians have a right to exist. And I think it's our role as a third country to make sure that there's fairness and transparency and accountability about a peace process.
'I always think these semantics about whether a country has a right to exist actually just ends up in gatekeeping, which is partly how we ended up in this mess in the first place of the Balfour Declaration.'
The Balfour Declaration was a 1917 statement from the British foreign secretary supporting the creation of a 'national home for the Jewish people'.