Drug-buying agency Pharmac has begun funding a new type of anti-depressant.
From 1 November, Mirtazapine will be subsidised for people with severe depression who have not responded to treatment.
This is the 16th anti-depressant drug to be funded.
Pharmac says it expects to save money from the move in the next five years because the only other alternative for treatment-resistant patients is more expensive.
The agency's medical director, Peter Moodie, says he has had a good response from doctor and patient groups about the drug's addition.