Police are reviewing a two-year-old criminal complaint against Whaleoil blogger Cameron Slater over material he used on his website.
The review is studying how Slater obtained a vast quantity of private emails which were used as the basis of posts on his blog.
It comes as police investigate a complaint from Slater over the hacking of his computer. Detectives investigating Slater's complaint this week executed a search warrant on the home of author Nicky Hager, who used material obtained by the hacker known as Rawshark to write Dirty Politics.
The police review stems from a complaint laid in May 2012 by businessman Matt Blomfield, who has taken a defamation case against Slater over articles on the Whaleoil blog.
Slater wrote on his blog that the articles were based on information held on a computer drive he had obtained. According to texts supplied to the Herald by Rawshark that are said to have been hacked from Slater's computer, the blogger talks of having more than 30,000 of Mr Blomfield's emails.
After Slater complained about the hacking of his computer, Mr Blomfield went back to police to ask why there had been no action over his case.
In a letter dated August 28 2014, Mr Blomfield said: "I am mindful of the fact that I have waited over two years for my matter to be concluded and I am becoming slightly impatient. If it came to pass that Mr Slater receives preferential treatment for a complaint that very closely mirrors my complaint I would be quite annoyed."
A spokeswoman for Waitemata police said Mr Blomfield's case was being reviewed by a detective senior sergeant who was currently on holiday. She didn't know how long the review had been going on, or when it was likely to be complete.
In a hearing earlier this year, Slater had sought the mantle of "journalist" in a bid to protect sources for the allegedly defamatory posts, including the source of the hard drive.
Justice Raynor Asher told Slater bloggers could be journalists and receive the protection but ruled the protection did not extend to stories about Mr Blomfield.
He said there were questions in the defamation proceeding which needed answers.
"In the ordinary course of events persons do not legitimately come by the personal hard-drive and filing cabinets of other persons. "Even if Mr Slater was not party to any illegality, it seems likely that the information was obtained illegally by the sources, and this diminishes the importance of protecting the source."
Justice Asher said there was an even lower public interest "in encouraging persons who are in a private dispute with others from going to the media with unlawfully obtained confidential material to hurt them".
"This material prima facie is in that category."
On Twitter this afternoon, Slater pointed to a letter from the Independent Police Conduct Authority which reported police saying the hard drive was found to have never been stolen.
The letter, sent to Slater, made no reference to whether police had investigated the accessing of the information, which is the subject of the current review.