His reservations about the re-shaping of A-levels are likely to reflect the findings of a report on modular exams due out next week from the Office for Standards in Education - which is led by Mr Woodhead.
From 2000, A-levels will be re-written as six-part, modular exams, allowing students to take a series of mini-exams as they progress through the sixth form.
But Mr Woodhead last week expressed doubt that the new structure permitted talented candidates to show a grasp of the whole of their subject. And he asked if universities would really be comparing like with like if they put an applicant who had passed a module after many attempts with one who had passed it first time.
"Are we moving to a situation where modular syllabuses will be the only kind available in some subjects?" he asked, adding that the traditional or "linear" approach based on a final exam must be preserved in all subjects.
Research to date suggests that candidates on modular courses produce a smaller number of A grades than those on traditional courses, but that the proportion of average grades is higher.
From September 2000, A-levels will be split into two equal parts of three modules each, with the first year reformulated as an "advanced supplementary" exam. Sixth-formers will be encouraged to study up to five subjects instead of three, the current norm.
The modules are comparable with the course units of vocational exams, allowing pupils to mix and match between the two. But the chief inspector said the plan to mix and match academic and vocational exams could "destroy the intellectual integrity" of A-levels.
Modular exams have attracted a number of high-profile critics. Addressing the same conference, Marilyn Butler, rector of Exeter College, Oxford, said Oxford University might have to reintroduce its special entrance exam because it would be so difficult to judge candidates on the basis of the reformed A-levels. Up to one quarter of the teaching time, she said, could be lost. She stressed that she was speaking in a personal capacity.
Some independent schools have also expressed doubts, warning they could switch to the International Baccalaureate.
But the new exam has the approval of the Secondary Heads Association. John Dunford, its general secretary, said the reforms were "a cautious step forward by the Government in the right direction".
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