Jeremy Corbyn has insisted there is no place for anti-Semitism within Labour and those guilty of anti-Jewish racism have been “brought to book”.
He urged the Jewish community to “engage” with him following outspoken criticism from the chief rabbi.
Ephraim Mirvis had claimed “a new poison – sanctioned from the very top – has taken root” in the party.
Mr Corbyn said anti-Semitism was “vile” and “rapid and effective” action had been taken against offenders.
At the launch of the party’s “race and faith manifesto”, he said anti-Semitism would not be tolerated in any form under a future Labour government.
He said no community would be “at risk because of its faith, identity, ethnicity or language”.
Mr Mirvis, the Orthodox chief rabbi of Great Britain and Northern Ireland, earlier warned that “the overwhelming majority of British Jews are gripped by anxiety” at the prospect of a Labour victory in 12 December’s general election.
The chief rabbi, who is the spiritual leader of the United Synagogue, the largest umbrella group of Jewish communities in the country, said Labour’s claim it had investigated all cases of anti-Semitism in its ranks was a “mendacious fiction”.
In an article for the Times, he asked people to “vote with their conscience” in the election.
Asked if he regretted not doing enough to tackle the issue, Mr Corbyn said internal processes for dealing with anti-Semitism were “constantly under review” and his door would be open to Mr Mirvis and other faith leaders to discuss their concerns if he entered Downing Street.
“Since I become leader, there are disciplinary procedure that didn’t exist before. Where people have committed anti-Semitic acts they are brought to book and, if necessary, expelled from the party or suspended, or asked to be educated better about it.
“I want to live in a country where people respect each other faiths and people feel secure to be Jewish, Muslim, Hindu or Christian.
“But be absolutely clear of this assurance from me. No community will be at risk because of its faith, identity, ethnicity or language. I have spent my life fighting racism.
“I ask those who think things have not been done correctly to talk to me about it but above all engage. I am very happy to engage.”
Labour has been beset by allegations of anti-Semitism for more than three years, leading to the suspension of a number of high-profile figures such as Ken Livingstone and Chris Williamson, and an unprecedented investigation by the Equality and Human Rights Commission.
A number of prominent Jewish Labour politicians, including Luciana Berger and Louise Ellman, have quit the party after being the subject of anti-Semitic abuse on social media while others have accused Mr Corbyn of personally endorsing anti-Semitic tropes and imagery.
‘Sense of fear’
Ms Ellman said the chief rabbi had been right to speak out and his remarks highlighted the “gravity of the situation” facing British Jews.
“It is unprecedented for a major political party – a potential party of government – to be perpetuating anti-Semitism,” she told BBC Radio 4’s World at One.
“This is not just about Jewish people, it is about the whole of our society.”
And former Lord Chancellor Lord Falconer, who had been due to lead an independent review into anti-Semitism before the equality watchdog intervened, urged the party to heed the chief rabbi’s words.
“We deserved an attack that strong,” he told the same programme. “We need to deal with anti-Semitism properly.”
He added: “I really hope that the chief rabbi’s absolutely extraordinary, but justified, intervention will be listened to by my party.”
But the Labour peer Lord Dubs, the child refugee campaigner who fled Nazi-occupied Czechoslovakia in the 1930s, said he was “bitterly disappointed” by the tone of the chief rabbi’s remarks.
He said he was reassured that Mr Corbyn – a longstanding campaigner for peace in the Middle East and the rights of the Palestinian people – was not personally an anti-Semite. He said where Labour had failed was in not acting “a bit quicker” in dealing with the issue.
The Labour leader faced criticism from Jewish groups when he said in last week’s general election ITV leader’s debate that the party had “investigated every single case” raised by complainants. He did not address the chief rabbi’s claim that 130 cases were outstanding.
Campaigning in Scotland, Conservative leader Boris Johnson said it was “clearly a failure of leadership” on Mr Corbyn’s part that he “has not been able to stamp out this virus in the Labour Party”.
But he faced criticism of his own party’s record on racism, after the Muslim Council of Britain accused the Conservative Party of “denial, dismissal and deceit” over the issue of Islamophobia.
South-African born Mr Mirvis became chief rabbi in 2013. In a Facebook post in July, he congratulated Mr Johnson on his election as Conservative leader, describing the new prime minister as a “long-standing friend and champion of the Jewish community”.
According to the British Board of Deputies, there are between 260,000 and 300,000 Jews in England and Wales. Around half belong to the Central Orthodox denomination which includes the United Synagogue, led by the chief rabbi.