Auckland author Ted Dawe said he was "blindsided" by the ban on his coming-of-age story "Into the River", which won the New Zealand Post children's book of the year in 2013.
"It's extraordinary," Dawe told the New Zealand Herald. "I've had quite a few emails from people who share that sense of outrage.
"Do we live in a country where books get banned? I'll get burnt next."
The book tells the story of a Maori boy who wins a scholarship to an exclusive Auckland boarding school but struggles with racism and drugs.
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The Film and Literature Board of Review said the ban was temporary and would be in place until the organisation reviews the decision next month.
A spokesman confirmed that no book had been subject to such a ban since current legislation was introduced in 1993.
The board took action after submissions from conservative lobby group Family First New Zealand, which said it objected to detailed descriptions of sex acts, coarse language and scenes of drug-taking".
Booksellers New Zealand chief executive Lincoln Gould described the ban as bewildering.
"It's not offensive, it's a quality book that has been acclaimed by the experts," he told AFP.
"It's most concerning that it's happening in this country.