Theresa May is facing a new storm of protest over the government’s post-Brexit immigration policies after ministers said that EU victims of human trafficking and modern slavery would have to pay a fee to remain in the UK after it leaves the European Union.

The admission, which angered groups campaigning to curb trafficking, drew claims that the Home Office was continuing to foster a “hostile environment” for migrants, however desperate their situation and deserving of help they might be.

The row erupted after immigration minister Caroline Nokes was asked by shadow Brexit minister Paul Blomfield whether fees that will apply under the EU Settlement Scheme would be waived for victims of trafficking and human slavery and their dependents after December 2022.

Although May has made tackling human trafficking and modern slavery a top priority, Nokes said in a parliamentary answer: “With regard to application fees, there are currently no plans to waive fees for victims of trafficking and modern slavery unless the victim is a child in local authority care. The application fee has been set below the cost of a UK passport and applicants have until 30 June to make the necessary arrangement to enable them to apply.”

Under Home Office plans, EU citizens seeking to remain in the UK after December 2020 will have to apply to stay through the new settlement scheme. The fee for remaining will be £65 for those over 16 and half that for those under 16.

Last night the Labour MP and chair of the Work and Pensions Select Committee Frank Field, who has been asked by May to chair a commission into the workings of the Modern Slavery Act, said his group would be “very much concerned” by the Home Office’s answer, which appeared to be part of an approach dictated more by a desire to control immigration numbers, than the interests of victims.

“We will want to look at whether the whole of modern slavery policy should be owned by the Home Office, when it is concerned with migration levels – and we as a commission are concerned with the victims.”

In 2016, after becoming prime minister, May described human trafficking as “the great human rights issue of our time”. Caroline Robinson, director of Focus on Labour Exploitation said: “The prime minister has made tackling modern slavery a personal priority. Yet by failing to remove fees for victims of modern slavery, the government is acting at odds with this priority and denying victims recovery and the hope of a better life.The government recently decided to slash financial support for potential victims of modern slavery in half, taking it down to just £37.50 a week, and this decision to charge them for registration compounds the financial stress they will experience. The harsh reality is that for many victims this fee will be very difficult to pay, leaving them open to the real risk of further exploitation.”

National Crime Agency figures showed that last year 643 potential victims of modern slavery and human trafficking arrived in the UK from other European countries, a rise from 610 in 2016.

Reacting to Nokes’s answer, Blomfield said May was “presiding over an immigration system that will force EU victims of these horrendous crimes to pay for the right to remain”. He added: “These are some of the most vulnerable people in our society. Many will not be able to afford the fee and will be at risk of further exploitation or of living in the UK without the correct documentation.If the Tories are serious about ending the ‘hostile environment’ policy they will drop these plans immediately.”

The controversy is the second involving Nokes to have blown up in recent days. Last week,, May’s former department was forced to reassure businesses that they will not be required to screen EU employees post-Brexit, after Nokes, speaking to the Home Affairs Select Committte, said they would have to conduct their own “rigorous checks”.