Jewish Labour supporters are said to be planning legal action against the party over its failure to deal with claims of antisemitism in its ranks.
Members are considering the move, according to the Observer, after becoming frustrated at the delay in addressing complaints against figures such as Ken Livingstone, Jackie Walker and Mark Wadsworth.
Jeremy Newmark, the chair of the Jewish Labour Movement, said the group was “seriously concerned” over “a vast backlog” of complaints and accused the party of letting the inquiry into Mr Livingstone to get “stuck in the system”.
Mr Newmark told the Observer: “We will be closely monitoring the outcomes of a number of high-profile cases due to be determined by the national constitutional committee over the weeks ahead.”
He called on the party to deal with Mr Livingstone before the local elections in May.
Some Labour MPs and party members are said to believe that action against Mr Livingstone, whose two-year suspension from the party ends in April, is being delayed to avoid damaging the party at the polls.
On Friday the JC revealed that a disciplinary hearing into Mr Wadsworth, who is alleged to have accused Jewish MP Ruth Smeeth of collaborating with right-wing media, had been postponed, with no new date set.
Mr Wadsworth’s hearing was due to have taken place on Wednesday next week.
In a House of Commons debate to mark Holocaust Memorial Day, Jewish Labour MP Louise Ellman, attacked groups that have claimed allegations of Jew-hate in the party are “slurs” against leader Jeremy Corbyn.
Mrs Ellman said: “Much speedier and stronger action must be taken by the party itself to challenge this unacceptable phenomenon.”
At a Redbridge Council meeting on Thursday evening, Wes Streeting, Labour MP for Ilford North, said the party's failure to tackle antisemitism was "abysmal".
Meanwhile, a member of Labour’s national executive committee faces criticism over a tweet claiming there is a “Jewish conspiracy” against party leader Jeremy Corbyn.
According to the Red Roar website, Mr Williams, who ran Mr Corbyn’s leadership campaigns in Wales, “liked” a tweet sent by Mike Hamblett, who describes himself as an eco-warrier.
The tweet also claimed “decent Jews” were not part of the conspiracy.
Mr Williams is a senior figure in Momentum, the hard-left group which moderates fear, has taken control of the party following last week’s elections to Labour’s national executive committee.