Rodney MP Mark Mitchell is likely to take legal action over Nicky Hager's book Dirty Politics.
The National MP says he is considering taking a defamation case after the September 20 election.
"Someone needs to be held accountable," he said.
Hager's book is based extensively on emails between National Party people and right wing commentators, especially Whale Oil blogger Cameron Slater and political strategist Simon Lusk.
Mitchell said none of his own emails feature.
But a section of the book alleges Slater and Lusk were involved in the Rodney National Party candidate selection process - purportedly backing Mitchell.
The 46-year-old is unhappy with the inference and said the selection process is much more thorough than what the book suggests.
The section where he features is "full of speculation and misrepresentation", he said.
Rodney National Party electorate chairwoman Jennie Georgetti said the selection process is democratic with a very detailed set of rules and guidelines.
"Rodney delegates make their decisions based on one-on-one meetings and three meet-the-candidate debates," she said.
"To suggest any of us were influenced by a blog that few people had heard of in 2011 and a second person we have never heard of is both insulting and ridiculous."
Mitchell said he's concentrating for now on his election campaign.
- Rodney Times
Debate has surfaced again about whether or not the haka should be performed before an international rugby match. What do you think?Related story: (See story)