Some centrist MPs have warned they could quit their roles to harm Mr Corbyn’s chances of replacing Theresa May at Downing Street.
Mrs May has a working majority of just 13 MPs, sparking fears the Tories could be ousted by Labour at the next election.
But veteran socialist Mr Corbyn still faces deep divisions within his own party, especially over Brexit.
Several Labour MPs have “already mentally packed their bags” and are ready to resign in protest at his leadership, according to Bloomberg.
The revelation comes less than a month after Heidi Alexander, an outspoken critic of Mr Corbyn, quit as Labour MP for Lewisham East.
The ex-shadow cabinet minister was reported to have been “forced out” of her role by Momentum activists in her constituency.
Following her resignation, Tory chairman Brandon Lewis said the Labour Party was “too divided to deliver on their promises to working people”.
He added: “This also highlights a complete lack of faith in Jeremy Corbyn and his leadership.
“The remaining moderates left within Labour will now rightly be concerned that they are next on Momentum’s list.”
Mr Corbyn has repeatedly come under attack from his own MPs for refusing to campaign for a second Brexit referendum.
Earlier this week, 16 London-based Labour MPs broke ranks by writings a joint letter urging him to change his position.
The signatories of the letter included six former shadow ministers, several of whom were in place until last year.
Mr Corbyn has also been accused of failing to tackle the scourge of anti-Semitism within Labour.
Last week he was accused of holding “problematic” anti-Semitic views by Jonathan Arkush, the ex-head of the Board of Deputies of British Jews.
He said: “He was a chairman of Stop the War, which is responsible for some of the worst anti-Israel discourse.
“He has never disavowed that sentiment. Is this double-speak? What are we supposed to think?
“If he shares the prevalent discourse about Israel, then that view is unquestionably anti-Semitic.”
A spokesman for Mr Corbyn rejected Mr Arkush’s claims, describing them as “unfounded and outrageous personal attacks”.
He added: “Jeremy has been absolutely clear that he is a militant opponent of anti-Semitism and is committed to driving it out of our movement.
“Our party has deep roots in the Jewish community and is campaigning to increase support and confidence in Labour among Jewish people in the UK.”