The Ministry of Health says it is aware that foreign visitors are using names of New Zealand relatives to get medical treatment.
Manukau Acting Mayor Arthur Anae said he was concerned that the practice was putting the lives of visitors at risk.
Mr Anae, who is also amember 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 previous 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," said Mr Anae.
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 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.
"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," Mr Anae 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."
A Ministry of Health spokesman said a patient would place their health at risk by assuming another person's identity. Although the ministry was aware of the issue, it had not received any official complaints from district health boards that it was a widespread problem.
DHBs did their best to check people's entitlement to funded services, the spokesman said.
