Kiwi patients have been harmed in more than 600 instances of medical blunders across the country in the past year.

This included 542 incidents reported by public hospitals and 86 reported by ambulances, the New Zealand Private Surgical Hospitals Association and aged care and hospice facilities, according to a Health Quality and Safety Commission report releasd on Friday.

The 542 "adverse events" reported by district health boards between between July 2016 and July 2017 was up slightly from 520 the year before.

It included 210 falls causing serious injury - 77 of which led to patients breaking their hip - and 282 incidents classified as "clinical management events".

These included 30 cases related to cancer or suspected cancer and 24 cases relating to eye treatments.

Medical items were also left in patients 17 times and eight cases involved either the wrong patient or wrong treatment.

Health Quality and Safety Commission chair Professor Alan Merry says these incidents can have "a huge impact" on the patient involved as well as their family and friends.

Because of this, the commission aimed to work with health care providers to promote "an open culture of reporting" such incidents so they could be better avoided in the future, he said.