In the OIA response, ACC said fewer than four of the complaints were considered "less than acceptable" conduct after being escalated to management or having a Code of Claimants Rights finding issued.
The remainder were found to be acceptable.
However, in many cases ACC said complaints are only recorded on a client's claim file, and are resolved without needing to go beyond the case owner.
"In most instances, these form the basis of a client's correspondence with their case owner and it is not easily identified in our system as a complaint."
ACC confirmed in the OIA response that the complaints related to privacy and customer service but should not be considered "definitive" figures, as the process involved using a free-text search of client feedback identified as complaints.
The agency told the Herald its HR team did a manual review of file descriptions of employment relations cases recorded in their system.
A review of these did not identify any access to sensitive claims without justification, but MSD said "some lesser" issues that may have been handled by a manager would not be identified in the search.
The agency defined "without justification" to mean where an employment issue was raised with HR relating to accessing a sensitive claim.
"If an access issue was identified following an employee ceasing employment with ACC for unrelated reasons, it will also not be identified in our search."
The Herald asked ACC for the average number of times a sensitive claim file was viewed by staff but the agency declined the request, citing that it would require a "substantial amount" of manual collation and research.
In a statement, ACC chief operating officer Gabrielle O'Connor said they ensure only staff who require access to sensitive claims in order to effectively and efficiently carry out the functions of their role have access.
"This access must be approved by their direct line manager, and then further approval is required by a Principal Adviser who has organisational oversight for the sensitive claims area."
O'Connor said each staff member's access permissions were reviewed quarterly and all employees with access to sensitive claims should only access a claim if they have a purpose to do so that supports the management of that claim.
Access of any claim without purpose by an ACC staff member is a violation of the code of conduct and can be considered serious misconduct, she said.
"Last year the ACC board and Treasury commissioned an independent review led by Wellington lawyer Linda Clark into how we manage client information. The review is expected to be completed next month.
"We are also working on a number of other improvement initiatives in system controls, privacy practices and footprint monitoring."
