ACC ministers, past and present, are being blamed for the corporation's failings identified in an independent inquiry report.

The investigation of a huge privacy breach says it was "genuine human error" which probably occurred because of systemic weaknesses within ACC's culture and processes.

Privacy Commissioner Marie Shroff and the ACC board commissioned the investigation by KPMG and former Australian federal privacy commissioner Malcolm Crompton after claimant Bronwyn Pullar was inadvertently emailed details of 6752 clients in March last year.

The report says ACC's response when it learned of the privacy breach in December was inadequate.

Eight days after senior managers met Ms Pullar on December 1, she was asked to return the information but did not, and the matter was not followed up until it appeared in the media three months later.

Ms Shroff says a culture change "starting at the top" is vital to prevent future privacy breaches.

She says the inquiry highlighted an "almost cavalier" attitude by ACC toward its clients and the protection of their information.

Labour's ACC spokesman Andrew Little says the report reveals "a litany of leadership gone wrong... a fiasco" and agrees change must start at the top.

"So let's start with ACC Minister Judith Collins - this whole fiasco is a direct consequence of the government clearing out experienced board members, putting in their own and overseeing strategies aimed at cost cutting rather than treatment and rehabilitation," he said.

"The cabinet that Ms Collins is part of has driven the agenda on this and she must take responsibility for the fallout."

The Greens say the government's focus on "saving a buck" caused ACC to lose sight of its role in helping injured and vulnerable people.

ACC spokesman Kevin Hague says the report shows former ACC minister Nick Smith's focus on "denying claimants every dollar he could" had driven a culture change.