Town halls have been ordered to take into their care migrant children who have arrived in the UK without parents or guardians.
A voluntary scheme will be made temporarily compulsory, meaning youngsters being looked after by councils on England's south coast will be moved to other parts of the country.
Immigration Minister Kevin Foster has written to all 217 local authorities with children's services, informing them of plans to "temporarily mandate the National Transfer Scheme" and giving them two weeks to say why they should not accept them.
Mr Foster said: "This decision has not been taken lightly but it is in the best interests of these children to make sure they receive the support they need."
The letter constitutes a "legal notice to accept transfers of children into their care, providing crucial placements to unaccompanied asylum-seeking children (UASC)" and is part of "urgent steps" to ensure "immediate, fuller participation" which is fair for all local authorities involved, the Home Office said.
Refugee Council chief executive Enver Solomon said: "Children who arrive in the UK on their own seeking safety are highly vulnerable.
“They must receive local authority care immediately, a responsibility that must be shared equitably by all local authorities in the UK.
"This important decision should reduce the unacceptable delays in vulnerable children, who have often experienced great trauma, getting the vital care they need and is a very welcome move."
Local Government Association chairman James Jamieson said most councils had offered help and authorities want to work "closely with Government to ensure the rights and needs of children are at the heart of these new arrangements".
He added: "Councils continue to face challenges in finding appropriate homes, with ongoing issues around centrally-led age assessment and delays in decision-making adding uncertainty for both councils and young people.
"These new arrangements must continue to swiftly take into account existing pressures in local areas, with greater join-up across Government to improve engagement with councils on all the programmes that support new arrivals to start new lives in the UK."
The move comes after under-fire Home Secretary Priti Patel was forced to defend efforts to tackle the Channel migrant crisis.
She told MPs councils should "play their part" in offering accommodation to asylum seekers.
Figures show the number of people who have made the dangerous journey across the Dover Strait in small boats so far this year is three times the total for the whole of 2020.
At least 886 people succeeded in reaching the UK on Saturday, taking the total for the year to more than 25,700.
Around 8,500 people crossed the Channel last year.
