The JC understands that the Equality and Human Rights Commission will announce an investigation into the Labour Party on Thursday.
In November, the Jewish Labour Movement (JLM), which voted on Wednesday to remain affiliated to Labour for at least another month, submitted a dossier of Labour antisemitism to the Equalities and Human Rights Commission.
It asked the EHRC to investigate the allegation that the Labour Party is institutionally antisemitic.
The Campaign Against Antisemitism also submitted a dossier earlier last year.