Eighty per cent of voters say Nicky Hager's best-selling book Dirty Politics won't make any difference to their vote.
In a Herald-DigiPoll survey, 750 voters were asked whether the book would change the way they voted.
A total 80.8 per cent responded no, 14.6 per cent said yes, with the remainder unsure.
Hager said the fact 14.6 per cent of those surveyed said they would change the way they voted on the basis of his book was "remarkable".
"Most people have made up their mind on what they're going to do.
"So if writing a book and revealing information that people don't know can affect 14 per cent of voters that's a fantastic sign of the power of the book and the power of the information."
The poll was carried out in the week to Wednesday.
Dirty Politics was controversially published last month and is based on emails hacked from right-wing blogger Cameron Slater.
The book claims the Government of Prime Minister John Key used blogs, including Slater's Whaleoil, to disseminate smears and scandals it did not want to be associated with.
The scandal's biggest scalp has been Judith Collins, who resigned as Justice Minister two weeks ago after a leaked email from Slater claimed she had been "gunning" for former Serious Fraud Office (SFO) chief executive Adam Feeley while she was minister in charge of the SFO.
Both Collins and Slater deny the claims.
Hager said he was not surprised most people said they would not change their vote. A reversed result would have been "bizarre".
"Most people aren't going to change their votes on this, or have their votes reinforced by this.
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" But to have that many people who are really thinking about it and are prepared to change their mind, potentially because of information, I really think that's tremendous."