The Ministry of Health says it is concerned that foreign visitors are using New Zealand relatives' names to get medical treatment, but that there is no indication the problem is widespread.
Acting Manukau mayor Arthur Anae has voiced concern that the visitors were putting their lives at risk.
Mr Anae, who is also a member of the Counties Manukau District Health Board, said he knew of at least two overseas visitors who had narrowly escaped death when they put down a New Zealand resident's name in an attempt to avoid paying hospital fees.
In one case, a woman required urgent medical care when she went into labour and went to hospital under the name of a New Zealand relative.
Doctors at the hospital, acting on the relative's previously recorded medical history, prepared a blood transfusion, only to find the patient had a different blood type.
"She nearly lost her own life and that of her baby through delay and perhaps even the transfusion," Mr Anae said.
In a similar case, a patient requiring emergency surgery gave a New Zealand identity, and escaped disaster at the last minute when the medical records were found to not match the patient.
"Although the patient's previous record indicated that he had undergone previous surgery, there were no scars to prove it.
"The result was a delay in transfusion and the patient's life was placed at a significant and unnecessary risk."
Mr Anae said he was speaking out about the issue because someone could easily be killed and he did not want hospital staff to be unfairly blamed.
"If I don't bring it to the attention of the communities that are doing these things, they think they are being smart and getting away with it," he told Radio New Zealand.
"But at the end of the day, someone's going to die and then they're going to turn around and point their finger at the hospital." Mr Anae said compulsory medical insurance on arrival in New Zealand would help put a stop to the problem.
The Ministry of Health today it was that anyone would place their health at risk by assuming another person's identity.
However, it said although the ministry was aware of the issue, it had not received any official complaints from DHBs that it was a widespread problem.
DHBs did their best to check people's entitlement to funded services.
However staff often had to take information provided to them in good faith.
