Jackie Walker, the former vice-chair of the hard-left Momentum group, who is currently suspended from the Labour Party, has had her case referred to the party's National Consitutional Committee (NCC).
The Kent-based activist, a leading ally of party leader Jeremy Corbyn, was suspended by Labour last September following comments she made about Holocaust Memorial Day.
At a meeting of Labour's NEC in central London today it was decided to push the hearing up to the party's NCC.
A decision could have been reached at today's meeting to throw the case out - but the allegations were deemed serious enough to proceed with further steps.
At last year's Labour conference in Liverpool, during a Jewish Labour Movement training session on tackling antisemitism, Ms Walker said Holocaust Memorial Day should remember genocides other than the Shoah.
She was told that the annual memorial did recognise other episodes of mass murder, but Ms Walker went on to claim she had not seen a definition of Jew-hate which she could “work with”.
At the same event Ms Walker questioned why Jewish schools needed particular security to protect themselves from possible attack.
Ms Walker had later claimed footage from the training session was leaked “with malicious intent” and repeatedly denied she was antisemitic.
She was subsequently stripped of her position as Momentum vice-chair.
Ms Walker had previously been suspended from the party after she wrote about Jewish people as “financiers of the sugar and slave trade”, but was then reinstated.
Marc Wadsworth, the Labour activist who was suspended from the party after he grabbed headlines for heckling a Jewish Labour MP at an antisemitism event, has alsp had his hearing referred to the NCC.
Momentum supporter Mr Wadsworth left Labour’s Stoke-on-Trent MP Ruth Smeeth in tears after accusing her of working “hand in hand” with the Daily Telegraph to damage Mr Corbyn last June.
Ms Smeeth said he had singled her out with “vile conspiracy theories about Jewish people”.
Labour’s NEC decided today to send Mr Wadsworth's case to the 11-member NCC – which has the power to expel individuals from the party.
Jeremy Newmark, Jewish Labour Movement chair, said: "These reported decisions appear to be a step in the right direction and could be a critical move towards the party beginning to turn a corner on this issue. However there is still a long way to go.
"Some of the cases referred to the NCC today date back over a year and should have been concluded a long time ago. Other cases previously referred by the NEC remain unheard by the NCC for many months.
"Meanwhile key promised changes to party rules and processes and the implementation of many of the recommendations from the Royall and Chakrabarti reports remain ‘under discussion’.
"The rhetoric of 'zero tolerance' needs to be matched with swift, firm and decisive action against antisemitism.”
This article has been amended to update the text