Auckland District Health Board has lost almost $10 million over the past decade in treating foreigners who do not pay.
This is after writing off more than $29 million as bad debts and a contribution from the Ministry of Health of about $20 million.
But despite the cost inexorably rising, Auckland City hospital says acutely unwell visitors without insurance will never be refused care.
Chief medical officer Margaret Wilshire says all patients are taken as they come in the door and often it is not possible to ascertain their eligibility because they are not in a position to provide it.
Visitor debt at Canterbury District Health Board increased from $823,000 in the year to November 2010 to $842,000 for the same period last year.