The Labour leader had been expected to be joined by his deputy, Angela Rayner, on Wednesday afternoon amid anger over his comments, which have sparked resignations from councillors.
In an interview with LBC after Hamas’s atrocity, Sir Keir suggested that Israel has the “right” to cut off power and water from Gaza.
But, acknowledging the “distress” caused by the remarks, he subsequently sought to clarify his position, arguing that he did not mean to back the siege on more than two million Palestinians.
Around 12 Labour parliamentarians, including at least one frontbencher, are believed to be at the meeting which began after Prime Minister’s Questions.
PA understands that Sir Keir had faced calls from the left of the party to expand the meeting to include a wider range of MPs.
“We fully recognise that this is a very difficult time for a lot of people, there are strong feelings on all sides of the debate here and it is important that he takes the time to sit down and listen to people from all points of view, which he has sought to do throughout this process,” a spokesman for Sir Keir said.
Labour frontbencher Darren Jones also insisted it was a “routine meeting”.
More than 150 Muslim Labour councillors have urged Sir Keir and Ms Rayner to back an “immediate ceasefire” in Gaza.
In a letter, the councillors from areas including Barking and Dagenham, Birmingham, Bradford, Blackburn, Bolton and Glasgow, said the leadership had to work to end the “humanitarian disaster”.
“As Labour councillors elected to serve our constituents, the message we have been hearing repeatedly over the past two weeks is simple, people just want to end the bloodshed and the loss of innocent life,” they wrote.
“No nation, no people or community should have to endure collective punishment and the same should be the case for the Palestinian people.”
In a sign of unrest too from within the parliamentary party, frontbencher Yasmin Qureshi used Prime Minister’s Questions on Wednesday to call the situation in Gaza “collective punishment” and ask Rishi Sunak: “How many more innocent Palestinians must die before this Prime Minister calls for humanitarian ceasefire?”
A spokesman for the Labour did not say whether Ms Qureshi – shadow minister for women and equalities – would be disciplined, but told reporters: “If I heard the question correctly… she was asking the Prime Minister what were the conditions that would lead the Prime Minister to support a ceasefire. And that was the question she was asking.”
Meanwhile, the South Wales Islamic Centre accused Sir Keir of having “gravely misrepresented” its meeting with Muslim leaders over the weekend.
The Labour leader had shared images of the meeting on Sunday, saying he repeated calls for humanitarian aid to enter Gaza and for water and power to be restored.
He said he was “questioned by members” and “made clear it is not and has never been my view that Israel had the right to cut off water, food, fuel or medicines. International law must be followed”.
But the centre apologised for the “hurt and confusion” caused by hosting Sir Keir.
“We wish to stress Keir Starmer’s social media post and images gravely misrepresented our congregants and the nature of the visit,” a statement said.
“There was a robust and frank conversation which reflected the sentiments Muslim communities are feeling at this time.
“Members of the community directly challenged Keir on his statements made on the Israeli Government’s right to cut food, electricity and water to Gaza, warranting war crimes as well as his failure to call for an immediate ceasefire.”
So far 37 Labour MPs, and former party leader Jeremy Corbyn, have backed a call for a ceasefire in the region, a position Sir Keir as well as the Government are not supporting.
The Labour leader has denied he ever backed Israel withholding humanitarian aid from Gaza.
Asked on LBC on October 11 if cutting off power and water was an appropriate response, Sir Keir replied: “I think that Israel does have that right.
“It is an ongoing situation.
“Obviously everything should be done within international law, but I don’t want to step away from the core principles that Israel has a right to defend herself and Hamas bears responsibility for the terrorist acts.”
But he has rowed back the remarks amid concerns within the party that it has angered voters, particularly in Muslim communities.
On October 2, he told broadcasters: “I know that LBC clip has been widely shared and caused real concern and distress in some Muslim communities, so let me be clear about what I was saying and what I wasn’t saying.
“I was saying that Israel has the right to self-defence, and when I said that right I meant it was that right to self-defence.
“I was not saying that Israel had the right to cut off water, food, fuel or medicines.”