Some schools have removed David Walliams books from their libraries following the publication of allegations against the best-selling children's author and comedian.
"Head teachers are already making difficult decisions about whether or not these books should remain on the bookshelves of libraries at the moment," said Pepe Di'Iasio, general secretary of the Association of School and College Leaders.
"I'm aware from several of our members that they've already taken the decision to take them off their shelves."
Walliams sold more than 50 million copies of books including Gangsta Granny and Billionaire Boy. He has denied allegations of sexual misconduct and abuses of power.
Speaking to BBC Breakfast, Mr Di'Iasio urged the government to give schools national guidance, so they are "not leaving this open to one or two head teachers making one decision and others making a different one".
Darren Morgan, head of Kings Road Primary School in Manchester, told the programme that he has taken the decision to remove Walliams' publications.
The stories have been useful to promote reading, but "when there are these allegations it's really difficult to keep these books on the shelves", he said.
Steve Chalke, head of Oasis Academies, which runs more than 50 schools, said it was impossible to stop children seeing the current stories about Walliams.
