Because the Wanganui directory has business and home phone numbers in one book, those opting out will miss out on both - but they will also be able to change their minds and opt back in again whenever they want.
To say you don't want a phone book delivered late next year, go to www.ypgbooks.co.nz or ring 0800 803 803.
Yellow is introducing the opt-out possibility gradually, around the country, in response to changing trends.
Ms Cornish said there were now three digital phone directory options. One was the white pages website, www.whitepages.co.nz .
Yellow has just launched an eBook telephone directory - a digital version of the paper book to help people making the transition. It can be downloaded to iPads.
Eighteen months ago, Yellow also launched a directory in a smartphone app. It's been downloaded 250,000 times.
People listed with the company have listings in all of those digital formats, as well as on paper.
But don't expect paper phone books to be a thing of the past any time soon. Ms Cornish says they still get a surprising amount of use - in Wanganui, people use them 260,172 times a month, according to Nielsen Consumer & Media Insights.
In some parts of New Zealand, use of the paper book is a third up, while in most it has stayed the same. Auckland people are most inclined to go digital.
"Auckland behaves quite differently to the rest of the country."
Because Yellow's charter obliges it to provide a free paper listing for everyone with a landline, the company had to get permission from New Zealand's new Minister for Communications and Information Technology, Amy Adams, to offer the opt-out scheme.
Increased use of cellphones is another feature of the changing world of communication.
Yellow will list cellphone numbers with landline numbers in its directories, for an extra cost. But Ms Cornish said it didn't aggressively pursue getting those extra listings.
"Some people like to keep their mobile number quite private, and a lot of people change numbers and providers quite regularly. There doesn't seem to be a call for it."