The adult art craze is driving a resurgence in book sales but many bookworms are colouring-in rather than reading.
New figures show national book sales jumped nearly 10 per cent in the year to date while sales of colouring-in books more than doubled.
While the craze is a boon for book sellers, bookshops are feeling the worldwide effects of a colouring pencil shortage, with German manufacturers admitting they can't keep up with demand.
Paper Plus Group spokesman Lyle Hastings said nine of the chain's top 20 titles over the past two months were adult colouring books.
"The sales trend is nothing short of amazing. The increase in adult colouring books over the last 12 months ranges from a huge 923 per cent increase on newer and more less-known books, to a whopping 36,600 per cent increase on key leading titles."
As soon as the books were on the shelves they were being sold, Mr Hastings said.
However, this had caused an unusual ripple effect, with leading colouring pencil manufacturers Staedtler and Stabilo struggling to keep up with the worldwide demand.
Mr Hastings said fiction sales had enjoyed an unexpected boost from a new Fifty Shades of Grey title, the long-awaited sequel to To Kill a Mockingbird and the continuation of Stieg Larsson's Millennium series.
Statistics obtained by the Weekend Herald from Nielsen's Bookscan yesterday show the popularity of the good old fashioned book is back with year-to-date sales 9 per cent up on the same time last year, following a decline in the preceding period.
The leisure and lifestyle genre, which includes colouring books, was the biggest mover, up 120.3 per cent, compared with a modest 2.9 per cent rise in 2014.
The top three colouring in titles were Millie Marotta's Animal Kingdom and Tropical Wonderland, and Mindfulness Colouring Book: Anti-Stress Art Therapy For Busy People by Emma Farrarons.
Pre-school and picture books reversed a 7.4 per cent sales decline last year to record a 17.4 per cent increase thanks to a surge in novelty books. The world/ideas/culture general interest category - which includes science and travel writing - was up 15.3 per cent compared with a 3.9 per cent slump a year ago.
The children's and young adult non-fiction category was the only genre in the top 10 to post a sales decline - down 4 per cent due to a drop in Minecraft sales.
The figures were released in time for today's inaugural NZ Bookshop Day, organised by Booksellers NZ, which will see participating stores dressing their shops and running quirky quizzes and competitions.
Booksellers New Zealand chief executive Lincoln Gould said the rebound in book sales began in September last year.
"And then we had a very good Christmas and then that much more positive trend was sustained and has been sustained for the rest of this year. It is good news."
Mr Gould said the adult colouring book craze was helping drive the turnaround, but non-fiction books always out-sold fiction overall.
"There's always a phenomenon each year, of course. One year it will be Fifty Shades of Grey, the next it will be colouring books, it's an international trend. It started in the US in the 2013/14 year and as the economy has picked up so too have book sales."
He expected one of the most popular titles for Christmas to be Dan Carter's biography which just needed its final chapter inserted - to hopefully mark an All Blacks' win.
Mr Gould said the digitisation of the book trade had also now passed, with e-reader sales estimated to plateau at 20 to 25 per cent of the market, matching international trends.