Mike Tomlinson, who once said he couldn't "give a monkey's toss" for teachers, now says he is concerned they will bear the brunt of badly-thought-out changes.
He told last week's annual meeting of the Association for Science Education that "the links between pre- and post-16 are not being thought out. They are being looked at separately, and it will be the poor teachers who will have to paper over the cracks."
Last week Mr Tomlinson, who taught science for 13 years, called for a "a much more fundamental" review of the science curriculum.
"We are trying to have a single curriculum to introduce all pupils to science, yet at the same time prepare a number as our future scientists. I am not sure the curriculum at the moment achieves that."
The national curriculum for five to 16-year-olds is currently being reviewed by the Qualifications and Curriculum Authority, for 2000. Broadening of the post-16 study is being considered separately.
A spokesman for the authority said the Government only wants a limited review.
"The QCA will aim to keep changes to a minimum in line with the original remit," he said.
Mr Tomlinson also told the association that the national curriculum has squeezed the flexibility and excitement out of science teaching.
He said: "I get bothered by so many pupils being bored. Kids should never be bored by science and technology.
"I am personally concerned whether we have got the right balance between practical and other work. It is long time since I saw a good demonstration lesson."
Ageing classrooms and laboratories were damaging science and information technology, he said.
"The adequacy of resources, staffing and accommodation are major problems which will only get worse as time goes on," said Mr Tomlinson.