Almost one third of Wairarapa voters don't know who they will vote for according to a phone poll this week.
Nicky Hager's book Dirty Politics is having an impact because many of those interviewed said trust was the main reason for their indecision.
The Wairarapa Times Age poll conducted by Whitireia Journalism students found 29% of the 417 voters interviewed are undecided about who to give their electorate candidate vote to.
The results show the strongest support for National, with 34% favoring candidate Alastair Scott, and 39% giving the current government their party vote.
However this is well down on the 49% electorate vote won by former National MP John Hayes in 2011, and on National's 47% party vote
In the phone poll, 17% of the party vote went to the Labour Party, and 20% said they would give Labour candidate Kieran McAnulty their electorate vote.
New Zealand first had 9% of the party vote and 11% of the electoral vote went to former MP Ron Mark.
The poll was conducted on Monday, September 1, two days after the resignation of National MP Judith Collins in the fall-out from the publication of Nicky Hager's Dirty Politics book.
The book was cited as a reason for doubt or changes to their 2011 vote by some of those spoken to.
"Because of Nicky Hager's book Dirty Politics I'm changing to Labour," one voter said.
"I'm usually a National supporter but I'm disgusted with the lot of them. With dirty politics and a lack of action for our communities I'm right off National" another respondent said.
"With all the rubbish going on I don't who I distrust the least," was another.
The percentage voters changing from their 2011 vote is significant, with 32% of voters changing their electoral vote and 22% their party vote.
The biggest beneficiary in this week's poll was New Zealand First's Ron Mark, who picked up 28 of the 101 electorate change votes. Ten voters also said they would change their party vote to NZ First.
"Ron Mark is a much more sensible and hard-working person to put in there," one voter said.
Of the 1069 calls made, 417 voters agreed to take part in the survey, which if extrapolated to the entire electorate would have a margin of error of 4.8% for an electorate of 46,315 enrolled voters.
Participants were randomly selected from phone book landline numbers in the Wairarapa electorate.
Notable comments about electorate vote choices were:
"I really like the NZ First guy (Ron Mark) but I want to get the
National guy out, and we have a better chance of that if we vote for
the Labour guy."
"Giving electorate vote to Labour rep because he has got out there and done the work and deserves a chance."
"Voting for Ron Mark instead of Labour, because I like Ron Mark and David Cunliffe promised to bring in more refugees, and we don't need more of the beggars."
"I approve more highly of the national candidate this time round."
"Electorate vote to Ron Mark because I feel he can do more for the community."
"Changed electorate vote to Ron Mark because he is looking for more radical policies."
Notable comments about party vote choices were:
"My vote hasn't changed for my party vote, I'm happy with the way that thing's are going at the moment."
"It's been a Labour vote for past 60 years, since I was a student. It will continue to be a Labour vote for me."
"I've always been a supporter of Labour, It's the way that our parents brought us up."
"I've voted National for the last 60 years but I'm not stuck on them. If Labour had more to offer I'd change my vote. Some people would vote National no matter what they did but I'm a swinger."
"Yes [my party vote is changing], with all this crap going on."