Health officials have found a case of a drug-resistant superbug that kills about one-third of all infected patients.

Candida auris is a fungus that causes invasive yeast infections in people with serious illnesses and weak immune systems, such as the elderly and the very young.

Infections occur mainly in patients who have spent a long time in hospital or aged care facilities, and who are hooked up to intravenous (IV) drips or catheters.

The Candida auris fungus cannot be treated with normal anti-fungal medication. Symptoms include a persistent fever and chills.

Te Whatu Ora says the infected person contracted the illness overseas, and it was monitoring the situation closely.

New Zealand hospitals had good infection protection procedures, it says.

Diseases expert Michael Baker says the case was another challenge the health system did not need.

The drug-resistant superbug Candida auris spreads by close contact.

Baker says more effort would have to go into infection control and cleaning in hospital and aged care facilities.

"It's obviously another burden that we don't want in our health system.

"It means that we will have some people who otherwise would have gone into a facility and come out again, who will die from this infection in the future.

"But it will be small numbers."

Baker says New Zealand hospitals have good infection protection measures, and it was possible the bug could be eliminated.

Bacterial and viral infections were much more common than fungal agents, which meant there was less research and development to find treatments, he said.

Drug-resistant illnesses were a growing problem and the risk was increasing, Baker said.

Cases of Candida auris in the US have spread rapidly in the past three years, although the numbers are still low overall.

RNZ