The national literacy framework is unworkable in mixed-ability classrooms, claims the National Association for Primary Education.
The Government's guidelines for teaching literacy, published earlier this month, could leave bright pupils bored and alienate the less able, says the association.
Its chairwoman Barbara Darley said: "This is the most significant government intervention in teaching ever. Not only are they telling us what to teach, they are telling us how to teach.
"The framework isn't statutory, although heads would never know that because everything we hear gives us the impression that it is. Frankly, I'm amazed the unions have been so quiet."
The association is calling on teachers to continue using their own methods, combined with the "choicest cuts" of the framework.
Ms Darley said: "They must look at it critically, there is some clear advice and examples of good practice which are really useful, but still we'd encourage teachers to go on trusting themselves and their own methods."
Professor Maurice Galton of Leicester University believes the framework will turn teachers into "technicians". "The Government has this obsession with what goes on in classrooms, when it should leave that to teachers," he said. "Applying different methods at appropriate times is what teachers are paid to do. Take that away and they become little more than technicians."
Brian Brown, head of Godmanchester primary in Cambridgeshire, is angry by what he describes as the "literacy strait-jacket".
"The idea that mixed ability groups can all happily sit through this prescriptive type of teaching shows no common sense whatsoever," he said. "I've got one 11-year-old reading War and Peace and another who loves talking about existentialist philosophy. But then I've got others who have the operational capacity of a six or seven-year-old."
However, former HMI Bill Laar called the framework "ambitious and intellectually informed". He said: "This does mark a revolution in government interference, so I'm surprised so many schools seem to have just quietly accepted it.
"But on the other hand, the teaching of reading has been the most contentious and vexed issue for years. The framework cuts through all the arguments at a stroke, and for that alone it's remarkable. " Psychologists' warning, page 8