The criticism by the Institute of Physics is the latest in a series of complaints submitted to the MPs' inquiry into testing.
The institute, whose 30,000 members include academics and teachers, said national curriculum tests were "blunt instruments that have a number of undesired consequences".
In a submission to the Commons education committee, the institute said exam results were so important to schools that no teacher could afford to ignore them. But it was far from clear that they improved learning because they limited the freedom of the best staff to teach as they saw fit.
Pupils' motivation and enjoyment was also being damaged by the frequency of testing, it said: most faced major assessments every year from 14 to 18.
This month, the General Teaching Council called for national tests to be scrapped because they placed an unnecessary burden on pupils. The council drew on a study conducted during the spring in which parents said the tests were more concerned with judging the performance of the school than their children's strengths and weaknesses.
One parent said that mothers of children in her son's class were annoyed after pupils were set 11 test papers to complete as homework over half a term.
The Institute of Educational Assessors, which represents 3,500 examiners, has told the committee that all external exams before the age of 18 should be phased out. Pupil progress would be checked by teacher assessment, with a small sample taking external tests at 16 to track national standards.
If the Government proceeded with plans to keep pupils in education and training until 18, retaining GCSEs at 16 would send out the wrong message, it said.
The Royal Society, Britain's national academy of science, has joined the attack on testing. In its submission to the committee it said that the present system was not "fit for purpose": it was stifling creativity in teaching and learning and contributing to the declining popularity of science and maths.
Professor Sir Al Aynsley-Green, the children's commissioner for England, called for the regime to be scrapped. "Children want to enjoy school, but they are concerned about the incessant pressures they are under because of tests," he told the committee. "Children feel under enormous stress in the school environment."