The report also found "wide and unexplained variation" in access to treatments for individual diseases across the country.
However, fewer Kiwis were dying from conditions that can be treated and that
premature death and disability caused by ill health is reducing.
The burden of disease from premature death and disability was similar to most other English-speaking and Western European countries, but per-capita spending on health care was lower in New Zealand than in most of these countries.
There had also been significant and sustained decreases in falls in hospital, which can lead to other problems such as blood clots or broken bones.
"Where national programmes have concentrated on reducing harm, in most cases these harms have reduced."
Improving quality of care was good for Kiwis, helping them live longer, healthier lives, and saved money, the report found.
"We estimate that the subset of reduced harms and potentially wasted expenditure
covered in this report has led to avoided costs of $90 million, and additional value to New Zealanders of nearly $400m."