A Queenstown employment consultant has lodged an official complaint about Inland Revenue (IRD) giving his details to social media companies.
IRD is regularly providing what it says are fully anonymised details of thousands of people to several platforms for targeted marketing.
David Buckingham has told the Privacy Commissioner he discovered this in May. He said it breached his privacy because the anonymisation was not effective, while at the same time the marketing was narrowly targeted and segmented.
The "hashing" process IRD relies on is not accepted overseas as adequate to anonymise personal data.
Buckingham said in his complaint this had left him feeling "violated, anxious and very upset from finding that a social media platform that has a reputation of having a disregard for the jurisdictions of sovereign nations like New Zealand, now has segmented details about my financial information without my knowledge".
He urged the commissioner to investigate if it was legal, and consistent with people's right to privacy.
IRD said last week after "enquiries and comments from the US Federal Trade Commission and European Data Protection Supervisor, we have begun looking further into the use of hashing to ensure it is still safe to use".