Child asylum seekers are being treated as adults in some parts of Wales, according to children’s groups.
The Welsh Refugee Council says care for children who cannot prove they are under 18 varies greatly.
Some local authorities place them in adult accommodation, occasionally prison, where they face deportation.
Councils say they are aware of the concerns and they are committed to finding the most effective way to conduct age assessments.
A person is “age disputed” when they tell officials they are under the age of 18 but do not have the documents to prove it.
It is up to local authorities to determine whether applicants are children.
Around 90% of age disputed people in Wales are from Afghanistan.
The Welsh Refugee Council, part of the larger Refugees Children’s Consortium, says children are not being protected because procedures are so poor.
It took two years for the authorities to accept he was a child. He’s now in a Welsh school
Chief executive Mike Lewis said: “Some Welsh councils are continually ticking the ‘no’ box, so there’s a real postcode lottery in how these young people are being treated.”
He said previous reports have highlighted a “persistent culture of disbelief” from Welsh councils that applicants were under 18.
There are no official figures for the number of age disputed people in Wales, but charities believe there have been around 150 cases in the last three years.
One child advocate called Sabeena told BBC Wales about one boy from Afghanistan called Amir who had a particularly difficult time.
“His father was murdered by the Taliban and he feared he was about to be recruited,” she said.
“He fled to Wales, but the authorities here didn’t believe he was 14.
“He had to share a bedroom with adults and was housed in a prison at one point.”
Sabeena says the boy was only believed when documents arrived from Afghanistan.
“It took two years for the authorities to accept he was a child. He’s now in a Welsh school and doing well,” she said.
“This could have been different if he’d been seen by a different council or even a different social worker.”
Child advocates claim councils are reluctant to assess asylum seekers as children because they have to pay care costs of up to £300 per child a week.
Campaigners say councils have an incentive to class young asylum seekers as adults
There is no Wales-specific policy on age assessments and children’s groups are calling on the Welsh government to do more.
The Welsh government says immigration is a non-devolved matter but guidance was published this September and training is being provided.
The Welsh Local Government Association said councils looked at each case on an individual basis.
“The WLGA is aware of the concerns surrounding the process and local councils are committed to working collectively and with the Welsh Government, the UK Government and the UK Border Agency to find the most effective way for age assessments to be conducted,” it added.