Michael Gove has raised concerns over the practice of giving children seeking asylum in the UK X-rays, amid fears they could be exposed to radiation.
The UK Border Agency (UKBA) reintroduced the controversial method of establishing children's ages in March 2012 but has since been condemned as "scandalous" as the procedure exposes children to unnecessary radiation.
The education secretary told an education committee on Tuesday: "We need to be clear that this is a proportionate, wise intervention in order to ensure that we can keep our borders safe.
"I am concerned obviously to ensure that we do not have people exploiting the generosity of this country, but I'm also clear that we should ensure that the dignity of individuals and in particular the rights of children are respected too."
Gove added he had told the Home Office and UKBA of his concerns but had yet to receive a response.
The former children's commissioner for England Sir Al Aynsley-Green voiced his anger at the time of the announcement, saying the procedure is "highly intrusive and carries a certain degree of risk".
A major argument against the decision to reintroduce the practice is whether the need for X-rays is still present as UKBA already take fingerprint and facial recordings.