A ban on Auckland schoolteacher Ted Dawe's controversial teen novel Into the River has been lifted by the New Zealand Film and Literature Board.

In a majority decision released today, the board said it no longer considers a ban on under-14s justifiable.

Although the book describes a number of "unacceptable, offensive and objectionable" behaviours, the board said the book "does not in any way promote them".

The book, which features sexually explicit content, drug use and use of slang for female genitalia, is now classified as unrestricted.

Auckland Libraries, which submitted to the board that the book should not be restricted, said it welcomed the board's decision.

"We have now started to make our copies available across our region's network of libraries," regional collections manager Louise LaHatte said.

"We have a long list of requests and customers who have been waiting will start to get notices advising they can pick it up from their local library."

Ready to roll: our copies of Into the River by Ted Dawe are now heading off to their hold customers & our shelves! pic.twitter.com/ui4mPWwcRY

— Auckland Libraries (@Auckland_Libs) October 14, 2015

Family First national director Bob McCoskrie, who started the controversy by sending the book to the Film and Literature Board of Review, expressed disappointment at the "flip-flop decision".

"A dangerous precedent has been set and parents will now feel disempowered and that their concerns will be ignored regarding similar books which they may not want their young teenagers and pre-teens to be reading," he said.

"The irony is that we could not read sections of this book on air or print excerpts in newspapers because it would breach broadcasting and media standards. Yet our children are more than welcome to it."

Board president Don Mathieson released a dissenting opinion, disagreeing with the result reached by the majority.

He believes the book's appropriate restriction is R18, or "at the very least" R14.

Mr Mathieson said he "completely disagrees" with the board's conclusion that the book "does not sensationalise, glamorise or otherwise favourably portray the sex, violence, cruelty, demeaning behaviour and other undesirable conduct which it describes".

However, the board concluded that the book's moral lessons were "clear and explicit".

And it found that the language used was unlikely to cause serious harm.