Members of the Campaign group of MPs held a conference call with the Labour leader to protest against Ms Long-Bailey’s dismissal as shadow education secretary.
But while they said the discussion had taken place in a “mutually respectful manner”, they made clear Sir Keir had stuck to his guns, saying there had been a “significant disagreement” between them.
The Labour leader’s office declined to comment on the talks, saying it had been a private meeting.
Ms Long-Bailey was fired on Thursday after refusing to take down a tweet linking to an interview with the actor Maxine Peake.
Ms Peake claimed police linked to the death of George Floyd in the US had learned their tactics from the Israeli secret services.
Sir Keir said he had acted in order to rebuild trust with the Jewish community after years in which Labour has been embroiled in allegations of anti-Semitism under his predecessor, Jeremy Corbyn.
However, the move infuriated left-wing allies of the former leader, including ex-shadow chancellor John McDonnell, who rejected claims Ms Peake’s comments were anti-Semitic and said he stood “in solidarity” with Ms Long-Bailey.
In a statement following its meeting with Sir Keir, the campaign group said it had also raised the issue of the freedom of party members to speak out on the issue of Israel.
“On the sacking of Rebecca Long-Bailey from the shadow cabinet, it was clear that significant disagreement remains on this point,” the statement said.
“The Socialist Campaign Group of Labour MPs made it clear that Rebecca Long-Bailey should not have been sacked and should be reinstated,” the statement said.
“The imminent annexation of the West Bank by Israel’s government was discussed and the need for the Labour Party, MPs, party members and supporters to speak out against Israel’s illegal annexation and ongoing human rights abuses by the government of Israel was raised.
“This was a businesslike exchange of views which took place in a mutually respectful manner.”