Migrants' rights experts have raised concerns that thousands of EU citizens living in Northern Ireland risk becoming illegal immigrants.

Today is the deadline for most EU nationals in the UK to apply to the EU Settlement Scheme. Under the terms of the Brexit agreement, EU citizens and their families living in the UK no longer have an automatic right to do so as freedom of movement has ended.

According to its latest figures at the end of March 2021, the UK Home Office says more than 86,000 applications have been submitted in Northern Ireland so far. But some experts are concerned thousands of people will miss the deadline.

Agnieszka Luczak, Manager of the EU Settlement Scheme support project at the Migrant Centre NI, said its service has been overwhelmed in the past two weeks.

"We did not expect that so many people have not applied to the scheme, we did not expect there would be so many people without valid forms of ID who would need to make paper applications, and the number of people who are still to apply is quite large."

Ms Luczak said they are very concerned, as people could potentially lose the right to reside in the UK, lose rights to access public services such as the NHS, and could also lose their employment.

"The government has put out guidance for late applications," she said. "However, if somebody just missed the deadline and they don't really have a reasonable ground, we don’t know what to expect and we don’t know how understanding the departments will be."

Applications are mostly made online and anyone who can prove they have been living in the UK continuously for at least five years before the end of 2020 can seek "settled status". Anyone who shows they have been here for less than five years gets "pre-settled status". This gives them the right to stay in the UK, but they have to make a later application for full settled status.

The UK Home Office said the process has "received overwhelmingly positive feedback". But some groups assisting people with applications said it has been significantly more challenging than the government anticipated.

Bernadette McAliskey, co-ordinator of the South Tyrone Empowerment Programme, an organisation which has been helping some EU citizens with applications, said it has been more difficult for vulnerable people or those living in precarious circumstances, as they may have issues with required documentation.

"It’s hardship for people without secure tenancies," she said. "It’s difficult for women who have left abusive relationships and maybe not had their documents with them."

Ms McAliskey said her organisation has assisted thousands of people, but she is worried they have not been able to reach many more.

"We think there are up to 20,000 EU citizens in Northern Ireland who won’t meet the deadline on the 30th. So we’re looking at a group of people who, in a matter of weeks rather than months, could go from being employed to being homeless and destitute."

The UK government said anyone who applies by the deadline will have all their rights protected even if a decision on their application is yet to be made.

People can still apply after 30 June if they have a "reasonable excuse".

A government spokesperson said the Home Office has made up to £22m in funding available for a network of 72 organisations, to contact hard-to-reach groups to help them with their applications.

The support will continue to be funded until "at least September", the spokesperson added.