Internet Party founder Kim Dotcom says he is building a libel case against blogger Cameron Slater, and has even considered hiring private investigators to track him.
Mr Dotcom says he decided to act after "200 plus smear stories" were published on the Whaleoil website, in what he describes as a "character assassination handled by the National Party".
He told Radio New Zealand he has been collecting evidence for his case for three months.
"My legal team has monitored the Whaleoil website, there are two junior lawyers that everyday go there to see what new defamation he is writing and they have been building a case."
Mr Dotcom said he had also considered hiring private investigators to follow Mr Slater and "had a meeting with a company that suggested surveilling Cameron Slater and getting some pictures and seeing who he is meeting."
But, he said: "I thought about my own GCSB experience and I felt very uncomfortable with the idea of doing that."
Mr Dotcom has been accused of being behind the hacking of Mr Slater's website and the leak of correspondence which led to the publication of the book, Dirty Politics.
He strongly denies the claims, and also said it was "unwise" of him to mention his dislike for Prime Minister John Key as an aside to a story about hacking into and changing the German chancellor's credit rating.