Police are reviewing a two-year-old criminal complaint against Whale Oil blogger Cameron Slater over material he used on his website.
Waitemata District police will look into how Mr Slater obtained the private emails of Auckland businessman Matt Blomfield, which were published on his blog.
Mr Blomfield laid a complaint with police in May 2012.
The review follows police investigations into the alleged hacking of emails belonging to Mr Slater.
Last week, police raided the home of author Nicky Hager in a bid to uncover the identity of the person who provided the information used in his book Dirty Politics.