ACC will apologise to about 7000 clients following a serious privacy breach at the organisation.
The corporation admitted on Tuesday details of more than 9000 claims were revealed to an outsider and says an Auckland staff member made a mistake when she sent an email with a spreadsheet attached in August last year.
About 250 of these claims involved the sensitive claims unit which handles claims by rape and sexual abuse victims.
Chief executive Ralph Stewart has apologised and says he didn't know about it until the Dominion Post reported the biggest privacy breach in New Zealand's history.
"It's no longer on the hard drive of the computer of the client who received it," he said.
"The information has been destroyed."
ACC senior management had reportedly been made aware of the breach by the email recipient about three months ago.
Fairfax reported ACC would be apologising to the 6748 clients whose privacy had been breached by email or telephone.
ACC says the email was sent on August 1 last year and the client who received it informed ACC in December, and was asked to immediately return the spreadsheet.
The emailed spreadsheet revealed the full names of clients, the nature of each claim, claim numbers and personal information.
ACC Minister Judith Collins has ordered an inquiry.
Labour's ACC spokesman, Andrew Little, says ACC executives should have revealed the privacy breach when they fronted up at a parliamentary select committee hearing two weeks ago.
"The whole issue raises serious questions over whether information has been deliberately concealed," he said.
Mr Little says affected clients may be entitled to compensation.