The heads say that it is imperative teachers are allowed more space to concentrate on the basics, given the Government's commitment to early intervention and target setting.
They want more flexibility in the curriculum, especially in the infant years, and have urged the Scottish Office and the Inspectorate to reconsider the 5-14 guidelines. "They are tramlines, not guidelines," according to Maire Whitehead, AHTS vice-president.
But Mrs Whitehead was encouraged by the response of Brian Wilson, the education minister, who has agreed to talks about a review of the primary curriculum.
Responding to pressure during a question-and-answer session, Mr Wilson said: "If a review is the way forward, we'll have a review."
The minister acknowledged the current investigation into 5-14 environmental studies, in particular the place of science, could be extended to allow a sharper focus on basic skills in the early years.
Mr Wilson was addressing the primary heads after they had unanimously agreed to press for less government control over the curriculum.
Mrs Whitehead said: "We're not doing justice to the children because we're spreading ourselves too thinly."
She wants more time on literacy and numeracy and less time on environmental studies and expressive arts - areas of the curriculum already under severe pressure.
Any time schools are inspected, heads are criticised if they depart from the national pattern, Mrs Whitehead pointed out.
"Something has to go and perhaps a little bit less here and there to art and design, music and PE would do. Maybe 5 per cent off environmental studies and expressive arts would help. People are very concerned about this in school and children are still being taught to read at P4," she said.
Older pupils could not take advantage of history and geography aspects of environmental studies because they did not have the "higher order" reading skills needed to glean information from books and CD Roms. "Comprehension skills need time," Mrs Whitehead argued.
She believed science should also be taught as a discrete subject to overcome the difficulties of fitting it into the present pattern of topics. Many teachers would rather have a programme of studies from P1 to S2, supported by experiments everyone could do.