My visa application was declined because of a health condition

There may be. Health requirements in Immigration New Zealand's instructions set out an acceptable standard of health, and applicants who are assessed as not meeting the standard may be eligible for a medical waiver, depending on their visa category. A waiver considers whether the person is likely to impose significant costs or demands on New Zealand's health services, as well as factors such as whether the applicant has family ties, is a partner of a New Zealander, or has skills of benefit. You can also provide additional medical evidence from your treating doctor showing your condition is well controlled and unlikely to require costly services. Look at the decision letter for review or appeal options, and act quickly. A licensed adviser can assist in compiling the waiver request.