The new drug, Keytruda, hailed as a historic step forward in the treatment of advanced melanoma, has been given only a low priority for taxpayer funding.
This will come as a blow to melanoma patients, some of whom are paying up to $300,000 to receive the drug, also called pembrolizumab, for two years. It is state-funded in Australia and England.
A spokesman for the Government's medicines-funding agency, Pharmac, said its clinical committees had reviewed the evidence and recommended that Keytruda have a low priority for funding.
He said that even though the committees considered it to be a drug with promise, there was uncertainty over the magnitude and durability of the benefits it provided for patients.
When asked if Pharmac ever gives funding approval to drugs in the low-priority category, he said it did and this tended to be when it made a deal with a supplier over a group of drugs.
"We are going to keep talking with the company [Keytruda supplier Merck, Sharp and Dohme] on ways in which we might fund it."