Winston Peters has taken legal action over the leak of his Superannuation details, targeting senior National party figures like Bill English, Paula Bennett and Steven Joyce.
Mr Peters' lawyer has today issued a legal document saying he wants to "identify and sue" the people responsible.
It requests Mr English, Mr Joyce, Ms Bennett and Anne Tolley hand over information about the leak.
It says Steven Joyce was heard at the National Party conference before the story broke saying there was a "full load" story coming out about Mr Peters.
It also names Ministry of Social Development chief executive Brendan Boyle and the former Prime Minister's chief of staff Wayne Eagleson as suspects in the leak.
The document names National Party staffer Clarke Hennessey, saying he is "the most likely person to have leaked the private information to media as part of a deliberate election campaign to damage [Winston Peters'] reputation".
Mr Hennessey says he strongly denies "any involvement in this matter or anything to do with Mr Peters' personal life".
The legal document is filed by Brian Henry, Mr Peters' best friend and lawyer.
It says: "The most likely explanation is that the leader of the National Party has sanctioned the leaking of my client’s dealings with MSD in a manner designed to damage my client's reputation."
Journalists Tim Murphy of Newsroom, and Lloyd Burr, of Newshub, are also named as they were both involved with filing the initial stories about the leak.