Professor Alan Smithers, director of the Centre for Education and Employment Research at Brunel University, said NVQs and their Scottish equivalent, SVQs, had descended into a game of "hunt the competence", rather than providing real, progressive training.
And he called for a wholesale restructuring of training to impose external tests, set umbrella standards for qualifications, design courses stating areas to be covered and separate the role of trainers and assessors.
Professor Smithers was speaking at the annual Perth College conference, organised with The TES Scotland, focusing on the role of post-school education in a competitive economy. He attacked the whole approach to vocational courses adopted by the National Council for Vocational Qualifications, arguing that NVQs had been designed simply by dividing jobs into a series of so-called competences - leaving qualifications with a plethora of units and performance criteria.
He said: "My argument is that there is a fundamental flaw. I believe mistakes were made in devising these qualifications, in going from the analysis directly into the qualification.
"Instead of the energy going into developing qualifications which develop people's skills, getting them into a better position to enjoy their lives, they are based on job analysis.
"The whole scheme has been hunt the competence, coming up with these lists of what people ought to be able to do."
Professor Smithers said many NVQs had been far too specific in their design, leading to a situation where 364 of the 794 NVQs had not been completed by anyone, while another 43 had only been completed by one person.
In Scotland the position is even worse as latest figures supplied by the SQA show 489 out of 793 SVQs are not completed - a take-up rate of only two in five.
At the same time around 16,000 vocational qualifications in England remain outside the NVQ framework. Employers have set up new non-NVQ courses and qualifications like the English BTEC National Diploma, which GNVQs were supposed to have superseded, have remained popular.
GNVQs were also singled out for criticism, with 13,683 completions in business studies comparing with 29,100 for the equivalent A-level.
In many cases, Professor Smithers argued, people started an NVQ programme,only to discover that they had simply to demonstrate skills they already possessed - rather than learning afresh.
At the same time, NVQs' reliance on specific units assumed knowledge was an "aggregation of bits".
"There are people who are good at juggling with balls, which does not make them good footballers; there are people who are good with their feet who are not good team players."
Professor Smithers said there were positive signs that some of the problems with the NVQ structure would be resolved in the relaunch of the qualifications due this summer.
But the conference heard calls for a rethink of vocational education in general to ensure courses and qualifications were matched to jobs, and students' needs and wants.
Dr James Murphy, of the department of educational research at Lancaster University, argued there was little evidence of a link between high educational achievement at degree level or beyond and Britain's economic performance.
He suggested that Britain was possibly the best education nation in Europe, certainly on achievement in higher education.
But his thesis was disputed by Stephanie Young, director of the Advisory Scottish Council for Education and Training Targets - the Scottish equivalent of NACETT in England and Wales.
She argued that while British achievement in higher education as high, there were major shortfalls in technical and craft training, putting Britain far behind international competitors like Germany.
Professor Smithers said: "Education and training is being used really as a rationing device for sharing out scarce jobs" arguing that education at one end of the age range and early retirement at the other, were occupying spare capacity in the job market.
"We have tended to want people in education and training whatever they are doing. What we have to learn in the next decade is how to use that time wisely so we can meet the needs of employers."