The UK government said Tuesday it is introducing legislation allowing bone and teeth X-rays to verify the age of asylum seekers suspected of falsely claiming to be minors.

The government is trying to curb what it calls "illegal" migration to the UK -- a highly contentious political issue.

Legislation unveiled this week by the justice ministry, which still needs parliament's approval, will "authorise the use of X-rays in scientific age assessments", the interior ministry said.

The interior ministry will introduce further laws specifying that X-rays of teeth and bones of the hands and wrists as well as MRIs of knees and collar bones "can be used as part of the age assessment process".

These tests are used in many European countries but some campaigners and medical professionals have questioned their reliability.

"Age assessment is an important process to help prevent asylum seeking adults posing as children as a way of accessing support they are not entitled to, and allow genuine children to access age-appropriate services," the interior ministry said.

Between 2016 and June 2023, there were over 11,275 asylum cases where age was disputed and almost half of the individuals (5,551) were found to be adults, it noted.

The government is under pressure to stop tens of thousands of migrants making dangerous crossings on the Channel from northern France in small boats each year.

It has introduced controversial legislation barring asylum claims by all Channel arrivals and other "illegal routes".

The new law also mandates their transfer to third countries, such as Rwanda, but both policies are on hold amid a court challenge over the legality of sending migrants to east Africa.

Britain's asylum system is also facing a huge backlog, a delay that rights groups assert is of the government's own making.