Winston Peters has been sending direct mail and setting up webpages in the names of random Kiwis, to the horror of some of those targeted who believe their privacy has been invaded.
New Zealand First have received 400 complaints about the marketing technique but at the same time, it has driven 66,000 people to their website.
Mr Peters sent the letter out, addressed to National leader John Key on Wednesday. Although the letter is directly addressed to Mr Key care of the recipient.
The letter criticises Mr Key, then directs Mr Key to a website - www.[recipient's name].MrKey.co.nz.
That website is a version of www.truthaboutwinston.co.nz, which has a supportive series of New Zealand First video clips.
The personal websites underwent a slight change yesterday, with a note added saying it is "not a real web page" because it does not have a registered domain and cannot be found by using search engines.
Yvonne Simms, of Mangonui, told the Herald: "I find the use of my name on a public website a gross invasion of my privacy. I have not given permission for my name to be used on the world wide web by him or anyone else. How low can a politician stoop?"
Kerikeri resident Wayne Andrewes was also angry. He said his wife, Lois, received a copy of the letter but did not want to comment.
"It may be legal but it's not ethical," Mr Andrewes said.
The letter that Mrs Andrewes received states New Zealand First policy and asks John Key "Have you got a problem with that".
"I've certainly got a problem with that," Mr Andrewes said.
He said using someone's name for a website address without their permission was an invasion of privacy.
University of Auckland political studies lecturer Dr Jennifer Lees-Marshment specialises in political marketing.
Dr Lees-Marshment said political parties were like businesses and would turn to the latest marketing fad when they were in trouble.
"And often they don't work or back-fire and get them into trouble," she said.
Dr Lees-Marshment said people were more likely to accept commercial marketing than political marketing because they were more used to it and because principles and values were associated with politics.
The Electoral Commission said it had received complaints, but it was a privacy matter rather than an electoral offence.
Privacy Commissioner Marie Shroff said the commission has received "quite a number of calls" on the issue.
"People calling us are concerned that their name may be published on the internet. As we understand it, the address is actually a link which re-directs people to the New Zealand First website. The Privacy Act does not extend to an MP acting in his or her official capacity," Ms Shroff said.
Mr Peters said he did not know how the website worked and referred the Herald to his adviser Damian Edwards.
Mr Edwards said the website idea was given to the party by a marketing company and the party apologised for any offence caused.
He said addressing the letter to John Key was a "marketing technique" and the letter and the website were electoral advertising, similar to letters sent out by other parties and was "not underhand at all".
Mr Edwards said he could understand how some people might find it offensive to see their name in an a web address but re-iterated that it was not a real website and only a link.
"There's always a risk you take when you use new technology," Mr Edwards said.
- With NZHERALD STAFF