Gordon Brown has said he believes Labour will adopt the internationally agreed definition of anti-Semitism as he declared the issue a fight for the "soul" of the party.
Labour’s ruling National Executive Committee is set to meet this week to decide whether to adopt the International Holocaust Remembrance Alliance’s (IHRA) definition of anti-Semitism in full.
It comes amid fierce criticism of the party leadership from the Jewish community and Jewish MPs over its handling of the issue.
Mr Brown told the conference Labour's unwillingness to adopt the full IHRA definition must end.
"It is time to say that this wrong must and can be righted," he said.
"This injustice has got to be remedied. This stain must be removed.
"The sore that exists and the harm that has been done and the hurt it has caused has got to be undone."
Mr Brown also called on the party to begin a comprehensive strategy against anti-Semitism "in all its forms", saying it was "not just a procedural issue" but "about the soul of the Labour party".
His speech came after another senior party figure claimed the Labour leadership has a “hatred of Jews”.
The former minister, who also attended the Jewish Labour Movement conference, told the Sunday Times: “All (the leadership) can think about is their internal Labour party and their hatred of Jews.
“Jeremy has allowed anti-Semitism and racism to run rife. He needs to renounce much of what he did.”
Former chief rabbi Lord Sacks meanwhile claimed a majority of Jews are questioning whether Britain is a safe place to bring up their children in the wake of the Labour anti-Semitism controversy.
The crossbench peer insisted Mr Corbyn must “recant and repent” over remarks regarding Zionism which he claimed risked engulfing the UK “in the flames of hatred”.
Shadow chancellor John McDonnell defended his party leader and urged Lord Sacks to discuss the issue with the leadership.
“Jeremy has made it absolutely clear we will protect Jewish members of our party from any form of abuse and anti-Semitism," he told BBC1's The Andrew Marr Show.
“I just say to Lord Sacks ‘you’ve got it wrong, come and talk to us’.”
It came in the wake of veteran MP Frank Field resigning the party whip after accusing the leadership of presiding over Labour becoming a “force for anti-Semitism”.
Mr McDonnell told the New Statesman: “Yes, I think there are people who are willing to leave the party.
“I think I’m saddened by that. I really am saddened and I’m disappointed.”
He insisted the party leadership had an “open door” for colleagues considering leaving.