Mr Blunkett is concerned that the School Curriculum and Assessment Authority has been over-hasty in attempting to implement Sir Ron Dearing's master plan for post-16 education, including re-vamped A-levels and a new form of AS level.
He has written to Sir Ron, chairman of SCAA, urging him to reach consensus with teachers and academics before pressing ahead with plans which, he says, are causing widespread anxiety.
The letter, which is also signed by Labour front bench education spokeswoman Estelle Morris, states: "There seems to have been little if any attempt to reconcile the views of providers with those of users. Given the catastrophic decline in the uptake of mathematics over the last decade, agreement on the way forward would appear to be essential.
"We are increasingly worried by reports that there is great dissatisfaction among those involved about both the consultation process and the time afforded to it."
There is increasing pressure on SCAA to slow down. The Royal Society and the Liberal Democrats have already urged delay while the Joint Mathematical Council, representing teachers and academics, says the pace of change will cause chaos in schools Further problems are being caused by Sir Ron's plan for an AS-level in the key skills of "number", "communication" and information technology. This idea is central to the project of raising standards for all pupils, not just the brightest. But it is currently in great trouble. Schools are believed to have largely rejected the idea.
As SCAA prepares for another major meeting on A-level it looks increasingly likely to recommend a delay to the entire timetable for re-drafting A-level syllabuses.
Whether ministers will agree to delaying such high-profile reforms shortly before a general election, however, is another matter.
SCAA has already come under substantial criticism from the mathematics estalishment for effectively requiring a major re-write of the A-level core in a matter of days. The authority wants to see calculator-free papers, an increased emphasis on notions of proof and more problem-solving - in part to meet the concerns of universities.
These were the recommendations which also emerged, belatedly, from the delayed Standards over Time report published jointly by SCAA and the Office for Standards in Education.
Gillian Shephard, Education and Employment Secretary, immediately endorsed the changes - even though the report itself found little evidence that standards have declined.
Many mathematicians support the direction of the changes. But there is almost universal concern that the proposals are being rushed, could prove unworkable and will cause chaos in schools The letter from Mr Blunkett and Ms Morris outline a number of the most common concerns, inviting Sir Ron's comments on them.
* The mathematics core is new; there is as yet no evidence about what changes are needed.
* There is no consensus about the role of post-16 maths.
* SCAA's own working group has said that this is not the right time for re-writing maths or science syllabuses.
* The views of teachers have not been fully taken into account.