Jeremy Corbyn is to hold an independent inquiry into anti-Semitism and other forms of racism, Labour says.
The inquiry, led by Shami Chakrabarti, former head of campaign group Liberty, will consult with the Jewish community and other minority groups, Labour said.
Mr Corbyn will also propose a new "code of conduct" on racism at Labour's national executive committee in May.
It comes after Labour suspended MP Naz Shah and ex-London mayor Ken Livingstone amid anti-Semitism claims.
The code of conduct will include guidance on "acceptable behaviour and use of language", Labour said.
It will make "explicitly clear for the first time that Labour will not tolerate any form of racism, including anti-Semitism, in the party", a statement said.
The inquiry's vice-chairman will be Professor David Feldman, director of the Pears Institute for the Study of Anti-Semitism.
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The inquiry, which will report in two months, will set out "clear and transparent" rules on how the party should deal with allegations of racism and anti-Semitism.
It will also detail training programmes for parliamentary candidates, MPs, councillors and others, Labour said.
Anti-Semitism and Zionism
- Anti-Semitism is "hostility and prejudice directed against Jewish people" (OED)
- Zionism refers to the movement to create a Jewish state in the Middle East, corresponding to the historic land of Israel - anti-Zionism opposes that
- Some say "Zionist" can be used as a coded attack on Jews, while others say the Israeli government and its supporters are deliberately confusing anti-Zionism with anti-Semitism to avoid criticism.
What's the difference between anti-Semitism and anti-Zionism?
Q&A: Labour anti-Semitism row
BBC political correspondent Ben Wright said Jeremy Corbyn would be hoping the announcement would "calm what was now a very angry, volatile atmosphere within his party".
Mr Corbyn said Labour was an anti-racist party "to its core", and the Jewish community had been at the heart of the Labour party and progressive politics in Britain for more than 100 years.
"There is no place for anti-Semitism or any form of racism in the Labour party, or anywhere in society, and we will make sure that our party is a welcoming home to members of all communities," he said.
The row, which comes less than a week before local elections in England, and for the devolved administrations in Scotland, Wales and Northern Ireland, exploded on Thursday when Mr Livingstone claimed Hitler supported Zionism "before he went mad".
He made the comments in an interview with BBC Radio London, in which he defended Ms Shah, the party's MP for Bradford West.
'Nazi apologist'
Ms Shah was suspended on Wednesday over comments on Facebook, including a suggestion that Israel should be moved to the United States. She later apologised.
In the interview, Mr Livingstone said: "When Hitler won his election in 1932 his policy then was that Jews should be moved to Israel. He was supporting Zionism before he went mad and ended up killing six million Jews."
He was later confronted outside the BBC's studios by Labour MP John Mann, who accused him of being a "Nazi apologist" in front of TV cameras. Other Labour MPs also condemned Mr Livingstone's comments.
Speaking on Radio 4's Any Questions on Friday Jonathan Ashworth, a member of Labour's shadow cabinet, said Mr Livingstone's comments were "deeply offensive, it was vile".
Mr Livingstone was suspended by Mr Corbyn, who said there had been "grave concerns" about the language used.
On Friday, he told Sky News he would make his case citing a book by controversial American Marxist historian Lenni Brenner, who he met in the 1980s.
"I'll just produce the evidence and I mean it's hard for somebody to decide to suspend me from the party here when all this was there 30 years ago in the public domain and nobody raised a peep," he said.