The Masorti, Liberal and Reform movements are in the vanguard of a campaign to bring to Britain at least 150 child refugees from Calais who have a legal right to live here.
A number of United Synagogue leaders are also said to support the Safe Passage UK campaign, which is trying to raise £300,000 to resettle children from the camp. Started by Citizens UK, it has raised £50,000 in three days.
The Jewish response to the campaign was launched by Nic Schlagman, trustee for Noam and Masorti Judaism, who said there had been pledges of tens of thousands of pounds more. The situation had become more urgent, he added, as the French interior minister had announced the government's intention to dismantle the camp housing 9,000 refugees.
"It's terrifying even with our best work, if the camp closes before we complete this process some of these kids will never be heard from again," Mr Schlagman said.
"I'd be very surprised if, when they close it down, they will have put anything in place to take care of even the most vulnerable. This is the story of refugees - their lives are cheap."
After visiting Calais for the eighth time over the past year to deliver donations collected from synagogues, he floated the idea of supporting Safe Passage UK at his Shabbat dinner table.
"We decided to come together as a family and raise £2,000 to bring a child over in memory of those who raised the money to bring across my grandmother [who came to the UK on the Kindertransport]. "It struck me maybe other Kindertransport families - who had similar stories and a sense of gratitude and were watching what was happening in Calais - would like to have an impact."
After two weeks of spreading the word, he has attracted more than £40,000 in pledges. Finchley Reform Synagogue will dedicate its High Holy-Day appeal to the cause.
"I'm keeping as best a record as I can. But every couple of hours I get another message saying someone else has gathered money."
Mr Schlagman's target for the community is £250,000, some of which has already been passed on.
"I'm quite overwhelmed. I had hoped this story, which was incredibly compelling to me and my family, would resonate across the community. Now I believe it does."
Through its legal work and fundraising, Citizens UK has reunited 40 child refugees with their families in Britain over the past year.
Charlotte Fischer, Citizens UK's senior organiser with the Jewish community, said the campaign also had personal significance.
"My grandfather came across in 1939, so when I see these refugees in Calais I find it hard not to think of him.
"I'm proud in Britain we accept refugees. I also feel like we have a debt. People protected us. My family were German Jews and other families raised money to get us here.
"It's time to pay forward."
