The School Curriculum and Assessment Authority is to meet the boards to discuss measures aimed at pegging costs when reforms come in. Sir Ron's reforms will see a big increase in the number of qualifications, with double the number of students taking the new AS-level, the national certificate and diploma and "key skills" courses.
Secondary schools in England and Wales are spending an average Pounds 40,000 a year each - a total of Pounds 200m - on 16-19 exams. The bill for 460 colleges is Pounds 100m, according to the leading associations representing heads and principals.
Ministers are understood to be seeking savings through more collaboration between boards, a further cut in syllabuses, reducedA-level costs to pay for the new AS-level and minimum changes to common-core A-level schemes already approved by SCAA.
John Dunford, president of the Secondary Heads Association, said: "There is a real problem here. But that should not deter us from sensible reforms. We must provide policies aimed at motivating pupils and students, then think of the costs."
Exam boards are anxious to avoid a showdown with the Department for Education and Employment but George Turnbull, spokesman for the Associated Examining Board, said: "If more exams are being taken by more people, it is inevitable that costs will rise. Remember, there are also rising numbers of sixth-formers in the system again."
Some were more cautious. Margaret Hutchinson, deputy chief executive of the Northern Examinations and Assessment Board, said, with new exams and bigger intakes, costs would obviously rise but estimates were premature.
Small or medium-sized institutions which cannot absorb economies or do deals with the boards could see fees doubling. Large schools such as Holland Park comprehensive would see a less dramatic effect. Headteacher Mary Marsh said: "Our present bill is around Pounds 70,000 and I can see it going to over Pounds 100,000 a year."
The moves come as Gillian Shephard, the Education and Employment Secretary, considers plans to impose payment by results on school sixth forms alongside sanctions already being introduced in colleges.
Teacher-union leaders fear a further exclusion of borderline candidates, as was seen with the introduction of league tables. Ministers' plans for payment by results could only worsen things, they warned.