By Ray Dunne
BBC News Online health staff in Llandudno
As many as one in 10 patients treated on the NHS may not be entitled to free medical care, it has been claimed.
Doctors suspect many patients exploit the NHS
Dr David Shubhaker, a GP in Essex, said 10% of his patients were foreigners who were not entitled to free care.
His comments came as doctors at the British Medical Association's annual conference discussed government proposals to introduce identity cards.
Doctors said it could help them to identify people from overseas who are not entitled to free NHS treatment.
The government is cracking down on the number of people who come to the UK from abroad solely to seek free medical care - so-called "NHS tourists".
While there are no accurate figures on how many people are involved, ministers believe it costs the NHS millions of pounds a year.
Dr Shubhaker, a GP from Gants Hill, Essex, said his "NHS tourists" came from many countries.
"Patients are coming from all areas - Somalia, Eastern Europe and other countries like India and Pakistan.
"They are usually relatives who are visiting and seeking medical help.
"We are not able to say no, and primary care organisations do not give us any
direction so it's up to the doctor's discretion."
BMA chairman James Johnson said the number of "NHS tourists" varies across the country.
"In some places there is a problem, but in some areas it is not a problem at all."
The government plans to introduce identity cards by 2012. Mr Johnson said it could enable doctors to identify those who are entitled to treatment on the NHS.
But he warned that doctors would not become immigration police.
"We have said that doctors are not there to police the system.
"We are not going to have GPs having fights in their surgeries over what is written on the card."
He added that doctors would need clear guidelines on who they should and should not treat.
But he insisted that they would always provide care to those who are seriously ill.
"Our ethical duty is to treat them," he said.
However, Dr Tiz North, a consultant radiologist in Carshalton, criticised the policy.
"If a patient comes to the hospital and does not have an identity card, will
we turn them away?," she asked.
"It is not the job of a doctor or nurse to decide who they are going to treat
and who they are not going to treat.
"The identity card is yet another government good idea which will be fine
when people are applying for benefits, but not for treatment."
Shadow Health Secretary Andrew Lansley said: "What is needed as a matter of urgency is an electronic patient record, which will make clear whether someone is eligible for treatment.
"However, the current problem faced by doctors is entirely of the government's making.
"Their shambolic handling of the asylum system has put huge pressures on the NHS and moral pressure on doctors who often feel forced to act as backstop immigration officers."