Kent CC has issued a claim for judicial review against home secretary Suella Braverman, asking her to direct other local authorities to ‘receive their fair share' of unaccompanied asylum-seeking children (UASC).
It said the number of UASC in its care was putting a ‘wholly disproportionate' strain on its children's services.
The national transfer scheme (NTS) means that statutory responsibility for supporting UASC can be transferred from an entry local authority to another UK local authority with children's services.
Kent said that between 1 January and 1 July this year, 648 UASCs arrived in Kent and were passed on to its children's services.
The council said that of these only 426 had successfully been passed on to other local authorities under the NTS.
Kent said the scheme's operation ‘sadly remains inadequate'.
Council leader Roger Gough and cabinet member for integrated children's services, Sue Chander, said: ‘Kent residents deserve a robust, long-term solution.
'This is well overdue and critical for the future welfare of all children supported by Kent.'