Jewish groups have condemned Labour for hiring a head of membership who shared a video which claimed allegations of antisemitism by party members are being used as a "political weapon" to "smear" Jeremy Corbyn.
Jules Rutherford, who is due to start the job on Monday, was found to have retweeted a post condemning the "smears against the party leader" on Thursday.
Jewish Labour Movement chair Mike Katz said it was "just awful, but who's surprised?"
He tweeted: "This is why EHRC are investigating the Party for institutional anti-Jewish racism following Jewish Labour's referral. In today's party, you virtue-signal by being casually racist."
In a statement, Mr Ktaz added: "This is yet another clear example - were it needed - that Labour's anti-Jewish racism is deep-seated and institutional.
"This is why JLM was right to refer the Party to the EHRC, and why it is now under investigation.
"This follows a pattern of appointments which has seen the factionalisation of party staff to an unprecedented degree and underlines the need for independent process when it comes to membership matters like discipline and complaints.
"Sad to say, this only serves to underline that the way to get ahead in the Party these days is to virtue-signal by being casually racist."
The tweet Ms Rutherford shared linked to a video in which Professor Norman Finkelstein described allegations of antisemitism as "witch-hunt hysteria".
He said: "Jews were the spearhead of the campaign to stop Corbyn.
"The British elites could not have got away with calling Corbyn an antisemite unless they had the visible support of all the leading Jewish organisations."
Board of Deputies president Marie van der Zyl expressed shock about Ms Rutherford's appointment.
In the video professor Finkelstein went on to claim that Jewish newspapers including the JC "are the enablers of this concerted conspiracy by the whole of British elite society to destroy Jeremy Corbyn."
The video was originally tweeted by an account called Jack Jazz with the comment: "This is Professor Norman Finkelstein on the antisemitism smears which are being used as a political weapon against Jeremy Corbyn. These smears are damaging the fight against real #antisemitism. PLEASE RETWEET IF YOU HAVE HAD ENOUGH OF THE LIES."
When PoliticsHome unearthed the tweet and contacted Labour about it, Ms Rutherford's Twitter account was subsequently deleted.
In a statement, a Labour spokesperson said: "We do not comment on staffing matters."
Ms Rutherford set up a petition to have Alastair Campbell expelled from Labour in May for saying he had voted for the Lib Dems in the European Parliament elections.
Mr Campbell asked: "This doesn't bode well for the 'review' of my membership does it?"