Some foreign patients could be charged for emergency treatment or for calling out an ambulance under new government plans for England.
Visitors from outside the European Economic Area already pay for planned hospital care.
Health Secretary Jeremy Hunt wants to save the NHS millions of pounds by extending the charges to A&E care.
The British Medical Association said doctors were meant to treat patients, "not to act as border guard".
A consultation is expected to be set up in the next few weeks.
Overseas visitors can currently receive A&E treatment, ambulance services and GP visits free of charge, but if the plans go ahead some treatment could be withheld until fees are paid, the Times newspaper reports.
http://www.bbc.co.uk/news/uk-34685022