Science teachers are the most dissatisfied with key stage 3. And mathematics teachers say their pupils risk missing out learning about the "real world", such as knowledge of mortgages and insurance.
The survey of schools in six local education authorities, carried out by the National Union of Teachers, found the most common complaint was over-prescription in subject content and not enough emphasis on pupils learning investigative skills.
The survey also found: "Teachers believe the level and tests in key stage 3 have less value than the public examination system which provides proper checks and balances."
Teachers of history, geography, information and communications technology said the subject content of their subjects is overloaded.
The union calls KS3 the "forgotten" key stage and said its inquiry was intended to inform national curriculum review. A copy has been sent to Education and Employment Secretary David Blunkett and to the Qualifications and Curriculum Authority.
The survey found: "Teachers of English are satisfied with the status and position of their subject in the KS3 curriculum. The debates among teachers of English of the early 1990s on the English national curriculum and its assessment seem to be fading."
But some important areas are being squeezed out. English oral work, drama and creative writing and media studies are believed to be under pressure.
Teachers of geography say they do not have enough time to cover many important aspects of physical geography, for example volcanoes, earthquakes, rivers and glaciers.
Overall, the teachers surveyed were concerned about the lack of continuity of the national curriculum levels between KS2 and KS3.