The Supreme Court has dismissed an appeal by former Labour Justice Minister Bill Jeffries and referred it back to the Privacy Commissioner for further consideration.
The case arose after the Privacy Commissioner asked Mr Jeffries to reveal how he had obtained personal details about two people who complained to her about possible breaches of their privacy.
The couple, Marc and Ivy Powell are Americans who bought a station on D'Urville Island, with permission from the Overseas Investment Commission.
Mr Jeffries received personal information about the Powells while acting in a legal proceeding against them.
After unsuccessful cases in the High Court and Court of Appeal, he was granted leave to go to the Supreme Court on the grounds that the disclosure sought was covered by litigation privilege.
The Supreme Court has ruled that the matter should be returned to the Privacy Commissioner to establish the context in which the information was obtained.