The annual general meeting of Finchley and Golders Green Constituency Labour Party was marred by angry scenes over a vote to stop a new member joining amid claims he had used antisemitic language on his blog.
Wednesday night's meeting saw a resolution to reject a membership application from Daniel Margrain passed by 44 votes to 18.
Mr Margrain had used a blog titled cultureandpolitics.org to express his support for Labour leader Jeremy Corbyn - but he had also admitted he could not support Jewish candidate Jeremy Newmark as the local candidate in June's election.
In one blog he labelled Mr Newmark "a hard-line Zionist and member of the Israel lobby who has lied about antisemitism".
Mr Margrain also wrote of "the over-representation of Jews in the capitalist ruling class that gives the Israel-Zionist lobby it's power".
The resolution proposed that Mr Margrain should not be allowed to join the party because he had used "antisemitic language", and "Zionist as a term of abuse" and given clear indication of supporting a non-Labour candidate in June's general election.
As voting on the resolution took place a group of supporters of Mr Margrain shouted out comments alleging “Jewish” media had targeted Mr Corbyn.
One CLP member told the JC: "It was absolutely disgusting to hear what people said.
"There were allegations it was another example of how the ‘Jewish’ press had launched a smear campaign against Jeremy Corbyn.
"How 18 people who are members of my local Labour CLP can come to defend this man [Mr Margrain] is beyond me."
Mr Newmark, who narrowly failed to win the seat from Conservative MP Mike Freer in June, was not present at the meeting.
Mr Margrain told the JC: "I was unaware that any conversations or vote had taken place or that my article was of any interest to anybody outside my circle.
"This is the first I've heard about any of this. I need it to be confirmed officially in writing and then I'll comment."
Sources said that of the 18 members of Finchley and Golders Green CLP who opposed rejecting Mr Margrain's membership application "a sizeable number, but not all" were members of the Momentum group.
One CLP member added: "What this episode has shown is the importance of members of the community remaining within the party and fighting back against extremist elements.
"It has also proven that we still have some way to go in educating some people on why the language used by someone like Daniel Margrain is completely unacceptable to the Jewish community."
Alon Or-bach, chair of Finchley and Golders Green CLP, said: "I cannot comment on an ongoing individual case, as it is still being considered.
"On the wider topic, I'm glad that the vast majority of members in our party support taking a firm stand against antisemitism.
"We still have work to do to ensure all in our party take use of such vile language seriously.
"It reaffirms the need for the rule change that Finchley and Golders Green Labour Party is pushing for alongside the Jewish Labour Movement, which will make antisemitic and racist actions a clear violation of membership."
Labour's Compliance Unit will now be forwarded the decision taken at the Finchley & Golders Green CLP's AGM to reject Mr Margrain's membership application. They will rule on whether to expel him from the party.