An Australian writer has ousted J.K. Rowling from the number one spot of most popular children's books in New Zealand.

Andy Griffiths' Treehouse series bumped the hugely popular Harry Potter series into second spot with Lynley Dodd in third place with her Hairy Maclary series.

The list was compiled by bookseller Whitcoulls, which canvassed more than 16,000 votes for its Top 50 books in 2015. Fiction reigned supreme with Kiwi kids. No non-fiction books made the list.

Twenty per cent of the books that appeared on the list were newcomers, while fantasy novels such as Suzanne Collins' The Hunger Games trilogy (no 11) and Veronica Roth's Divergent series of books (17) remained popular. Famous writers, novels set in fantasy worlds and classic stories where humour is a feature, gained the most votes in the Top 50 books this year.

Andy Griffiths.
Andy Griffiths.

Many of the books that feature in the top 10 are illustrated books by classic, bestselling writers, including Maurice Sendak's Where the Wild Things Are (5), Roald Dahl's Matilda (6), Eric Carle's The Very Hungry Caterpillar (7) and Julia Donaldson and Axel Scheffler's The Gruffalo (9). Also making an appearance in the top 10 at number eight is New Zealand book Baa Baa Smart Sheep by Mark and Rowan Sommerset.

One major newcomer was Girl Online by YouTube phenomenon Zoe Sugg, aka Zoella. Sugg was the first major YouTube vlogger to have her book published and both Girl Online and a number of recently published titles have gained favour with Whitcoulls' teenage customers.

Whitcoulls Book Manager Joan Mackenzie said Kiwi kids were reading more than ever and favoured print books over electronic versions.

Ms Mackenzie said she was delighted to see 10 new books make their way into the Top 50. Comedian David Walliams, in a second career as a children's author, has two books in the Top 50 this year, Awful Auntie and Gangsta Granny, both written in the style of Roald Dahl.