Eleven mental health patients receiving inpatient treatment committed suicide during 2007.
A report on mental health issued on Sunday by district health boards summarises 216 incidents.
About a third related to the suicides of mental health outpatients. Others involved assaults, deliberate self harm, or clinical management problems.
The report says not all events were preventable or the result of error.
The Mental Health Commission says the 216 incidents represent a small portion of the estimated 100,000 mental health "contacts" per year.
The Mental Health Commission's chairperson Peter McGeorge says many problems arose when patients were transferred between mental health services or providers.
He says a lot more work needs to be done to ensure transitions are seamless, and that staff communicate about patient care.
A spokesperson for the 21 district health boards Murray Patton says mental illnesses are associated with high rates of morbidity and mortality.
He says DHBs review all incidents to see if improvements can be made, but not all are preventable, or the result of error.
Dr Patton says if recommendations are made, most mental health providers have systems in place to check they are implemented.