A 77-year old man died after significant blood loss during an operation - done by an inexperienced neurosurgeon, helped by surgeon not employed by Health NZ Southern

Open Justice reports the man died after suffering loss of brain function.

The man had been admitted after a heart attack - and had surgery for a benign optic nerve tumour that was causing headaches.

Aged Care Commissioner Carolyn Cooper criticised Health NZ Southern's lack of protocols - and inappropriate use of a different surgeon.

Extra surgery was also performed beyond the scope of the patient's consent form.

Health New Zealand says it's made changes.