Britain's decision to leave the EU is already having an impact on the recruitment of European staff, experts have said.
Anecdotal evidence suggests health workers who had agreed to come and work in the UK have decided not to come following the referendum.
And uncertainty surrounding what will happen to EU nationals in the UK after Article 50 is invoked could also have an impact on the workforce, health experts have predicted.
Current figures show that one in 20 NHS staff in England are from EU countries, including nine per cent of doctors and seven per cent of nurses.
When asked if the NHS is struggling to recruit European staff following the referendum, Professor Jane Dacre, president of the Royal College of Physicians, said:
Stephen Dalton, chief executive of the NHS Confederation, added: "On the EU workforce that is already here, there is concern amongst that workforce as to what will happen after Article 50 is triggered and what happens two years on. People are planning their futures and thinking about where they want to be in two years' time and three years' time and they won't wait to find out.
"There was an immediate move by Jeremy Hunt to issue a letter talking about how valued (EU staff) are and that was good but we need to move on from just telling people that they are valued to giving them some security that they will have some legal safety to remain in this country. Otherwise what we could see is a lot of people who are already here who will actually leave."
- 'Patient care will deteriorate in 2016/17'
The comments come as a new report finds more than a fifth of NHS finance directors believe patient care will get worse over the next year.
Concerns centre around growing waiting times, patients' ability to access services and potential cuts to the range of services the NHS will be able to offer.
The report, from the Healthcare Financial Management Association (HFMA), included the views or around 200 finance directors in England.
A Department of Health spokesman said: "We are investing an extra £10 billion a year by 2020 so the NHS can introduce its own plan for the future - by clamping down on rip off staffing agencies and investing in prevention and community health services to relieve pressure on hospitals."
- Impact of Brexit on NHS finances
But in a blow to the government, a separate report has found leaving the EU poses serious risks to NHS finances.
The Health Foundation estimated that the NHS budget in England could be £2.8 billion lower than currently planned in 2019/20.
If the UK is able to join the European Economic Area the NHS funding shortfall could be at £19 billion by 2030/31. If it cannot, the shortfall will potentially be as high as £28 billion, the authors said.
Anita Charlesworth, director of research and economics at the Health Foundation, said: