Sacks defended his comparison of Corbyn's comment which was insensitive to British Zionists' feelings, with Enoch Powell's racist "River of blood" speech against immigration in the 1960s.
"This is not about electoral prospects", he said, "it is about tackling the issue itself".
The MP for Barking warned that even if the party's ruling National Executive Committee embraces the full IHRA definition of anti-Semitism - which it had refrained from doing - it would not be enough to fix the damage.
Ahead of a crunch meeting of the ruling National Executive Committee on Tuesday, leading MPs have insisted the party must finally adopt the definition of anti-Semitism set out by the International Holocaust Remembrance Alliance (IHRA) in full. "Do what is right for Britain and then we can have further conversations".
The comments come in the wake of veteran MP Frank Field resigning the whip Friday after accusing the leadership of presiding over a party which is becoming a "force for anti-Semitism" and a host of other actions that have dogged Mr. Corbyn's leadership.
Veteran Labour lawmaker Frank Field, who has sat in the House of Commons for nearly 40 years, quit the party's group in parliament Thursday over the mounting anti-Semitism allegations.
In the past month, Mr. Corbyn has been criticised for his presence at a wreath-laying ceremony in Tunisia in 2014, which was said to have honoured the perpetrators of the 1972 Munich terror attack.
Mr Corbyn said he had attended to take part in a ceremony honouring innocent victims of a 1985 Israeli air strike.
Lord Sacks, Britain's former Chief Rabi, said on the BBC's Andrew Marr show on Sunday that he knew Jewish families who were thinking of leaving the UK.
Blair, whose centre-left agenda led the Labour Party to victory in two consecutive general elections, said the current crisis is not only alienating Jewish people but also more moderate voters who don't recognise themselves in Corbyn's more left-wing politics.
He went on: "I don't understand why there is this sort of pre-emptive move to split off".
Sacks the BBC's Andrew Marr he knows of Jewish families that are already planning to leave Great Britain due to their fear that the Labour leader-should he become prime minister-would unleash a new wave of anti-Semitism.
Mr Willsman's candidacy was placed.
"I think his world view and his vitriolic hatred of Israel, not a particular government of Israel, his vitriolic hatred of Israel, and I expect the rejection of the concept of Zionism itself, has blinded him to the company he is keeping".
"So the issue for me is I'd want to avoid at all costs a split if we can". "I've read a number of legal advices that say that we can".
"I don't want to live in a society where Jewish pupils need extra security at schools, and Jewish cemeteries are drawn on with Nazi swastikas".
He told the party to "belatedly get its act together" and "demonstrate the leadership qualities which have been lacking".