Prof Ron Paterson yesterday presented the annual University of Otago public health lecture, in which he explained the inquiry's work and the philosophy behind the 40 recommendations in its report, released in December.
The Government, which got the report in November, made its formal response late May.
"The delay was understandable because we had called for and written the report in a way that required cross-government action, and there was also the Christchurch mosques attack," Prof Paterson, speaking at Otago Museum's Hutton Theatre, said.
"The Government responded strongly to the challenge of our report, accepting the call for a transformation in New Zealand's approach to mental health and addiction."
However, the Government did reject one significant call by the inquiry, to set a reduction of 20% in the suicide rate; it instead preferred to aspire to zero deaths by suicide.
"I note that our report said we should be aspiring to a zero suicide [rate], and that no suicide rate was acceptable," Prof Paterson said, adding he was glad the Budget had put more resources into suicide prevention.
The inquiry received 5200 submissions and held 26 public forums and more than 400 meetings.
Key proposals included repeal and replacement of the Mental Health Act; a significant increase in access to mental health and addiction services; making mental health a specific focus of the primary health care system, and bracing the consumer voice in creating mental health and addiction programmes.
"Of course, the devil is in the detail," Prof Paterson said.
"Three key recommendations on alcohol and drugs have been referred for further consideration ... we also don't yet know if the to-be-formed Mental Health and Wellbeing Commission will be an independent ... or an autonomous crown entity."
Prof Paterson said that the recent inquiry was the sixth investigation into mental health held in New Zealand, but did not think it would be the last.
"I don't regard it as a failure if we have another report another generation from now ... what is important is that we now have a very clear view of the crisis and have asked the people what their response was."