ACC Minister Judith Collins has asked for an urgent report into allegations that private details of thousands of ACC claimants were sent to an unauthorised recipient.
Some 9000 ACC claimants, including sexual abuse and rape victims, had their details emailed to someone who should not have received them, Fairfax Media reported.
The details include full names and the nature of individual's claims - including those of 250 people handled by the ACC's sensitive claims unit.
Ms Collins this morning asked ACC chief executive Ralph Stewart for a report into the matter.
ACC's senior managers were reportedly informed about the breach three months ago but made no effort to investigate or ensure the information went no further.