Dozens of child asylum seekers formerly from the Jungle camp in Calais have launched a legal challenge to Home Secretary Amber Rudd.
Lawyers say 28 of them want written reasons for the determination that it was not in their “best interests” to be relocated to the UK.
They are seeking a judicial review in the High Court early in the new year.
A Home Office spokeswoman said: “It would be inappropriate to comment on ongoing legal proceedings.”
Eleven of those refused entry are aged 14, seven are 15, nine are 16 and one is 17. Sixteen are from Eritrea, 11 from Afghanistan and one is from Sudan.
Eight more waiting to have their cases determined are also involved in the legal bid.
They were dispersed to 15 reception centres around France when The Jungle camp was dismantled at the end of October.
The legal challenge is over a scheme named after Lord Dubs, who secured an amendment to the Immigration Bill for unaccompanied child migrants to be brought to the UK where they do not have family links but are considered to be at risk.
Toufique Hossain, of Duncan Lewis Solicitors, the firm behind the legal challenge, said: “Shortly before the Christmas break hundreds of unaccompanied children formerly resident in the Calais Jungle before it was demolished by the French authorities, whose plight had been the focus of cross-party Parliamentary attention in the run up the the Dubs amendment requiring the UK to take its fair share, were refused entry to the UK, summarily and without reasons.
“The children have been waiting months for the government to formulate a policy and now the policy has failed to allow the relocation of many of the most vulnerable children to the UK, in respect of whom the minister had promised to be ‘flexible’.
“In fact the way in which the criteria were drawn meant that most of the children from the Jungle were refused.”
The government pointed out that 900 child refugees had been transferred to the UK in 2016.
It has not said how many of these were brought to the country under the Dubs amendment, as opposed to those with relatives already in the UK.