Drug-buying agency Pharmac is to fund two new medicines to treat rare illnesses.
An agency spokesperson said one of the diseases, a rare form of tuberculosis, could have significant effects if it spread.
There was a risk of the disease spreading and becoming established in the community, the spokesperson said.
The drugs include bedaquiline, which has the brand name Sirturo, and siltuximab, which is sold as Sylvant.
Bedaquiline is used to treat the form of tuberculosis, which is resistant to multiple other drugs, and will be funded as soon as it received Medsafe approval, the spokesperson said.
Siltuximab treats a rare form of immune system disorder, and will be funded from June.
Pharmac has also funded two other new drugs for rare disorders this year, under a $5 million contestable funding process.