One national method of baseline assessment - by which children are tested for ability upon starting school - could be used to grade teachers, set budgets and compare children, they fear.
The 15-strong group has written to Education Secretary David Blunkett urging him not to impose one national system in favour of the current 91 accredited schemes. Government curriculum advisers claim that teachers would prefer one system because it would be easier to use.
Professor Geoff Lindsay, of the University of Warwick, said: "The purpose of baseline assessment is to help teachers understand a child's need in order to enhance their learning. If that's so, then we have no need of a single scheme which could be used for other purposes such as performance pay."
Dr Peter Tymms of the University of Durham, said: "Children will not best be served by a monolithic system - this isn't an exam-type test."