"We take our responsibility to protect the confidential health information of the people in our care extremely seriously and while this is an isolated incident of human error, we will be taking the opportunity to re-enforce to DHB staff the importance of taking every precaution to ensure the absolute confidentiality of all patient records."
The Herald on Sunday learned of the document spill just as Lakes District Health Board chief executive Ron Dunham was forced to apologise for a separate incident in which a document containing coded information on patients who had undergone abortions was released.
Read more: Lakes DHB apologises for privacy error
The file was mistakenly given to media as part of a response to an Official Information Act request.
It did not contain any names of the 625 women but it featured their National Health Index number, date of birth and ethnicity of the patients who had used the DHB's termination of pregnancy service.
"Although the women cannot be identified by coded information released, we are taking the situation seriously," Dunham said.
"The DHB is working closely with the Ministry of Health and the Privacy Commissioner.
"I understand the concern this will cause for the affected women and I apologise."
Dunham said the data had been released by a junior staff member who was assisting on the OIA request. The staff member had not followed standard process, he added.
A helpline was yesterday established to provide assistance for any woman concerned her details had been released. That number is 0800 525371.
Two of New Zealand's most embarrassing privacy breaches in recent years involve the Accident Compensation Corporation.
In 2011 an ACC manager inadvertently sent a claimant the details of 6748 other ACC clients, including some who were looked after by ACC's sensitive claims unit.
Two years later a case manager's notebook was stolen from a Christchurch property.