Schools should upgrade their furniture to meet the new European standard, which came into force last year, the British Educational Suppliers Association (Besa) said.
Research showed European children's height had increased by 10cm over the past 80 years - yet standard school furniture had shrunk by nearly 20cm.
Dominic Savage, Besa director-general, acknowledged it would cost at least pound;1 billion to replace the cheapest pound;6 plastic chairs with pound;100 ergonomic table-and-chair sets like those now provided in much of mainland Europe.
He said much of that money was already available through Building Schools for the Future and primary capital funding but using it to buy larger desks and chairs is not compulsory.
"New furniture must take account of the new standard or I would regard schools as being negligent, perhaps abusive," Mr Savage said. "The standard should be compulsory, or at least well promoted to schools by the Department for Children, Schools and Families."
Besa members appeared before the all-Parliamentary group for education on Wednesday, chaired by Labour MP Eric Joyce. Besa sponsors the group.
MPs heard that studies of 1,500 children found their torsos were longer, in proportion to their arms and legs, than they had been in the 1960s. And research commissioned by the charity BackCare found that around one in five pupils suffered recurrent back pain by the age of 16 after adopting a poor posture at low desks and chairs. In one in four cases they took time off school.
The new European standard now requires that the seat of a chair for teenage pupils be 46cm high, and the desk be 76cm high. Even nursery children need bigger furniture: their chair seat should be 26cm, and their table 46cm.
John Dunford, general secretary of the Association of School and College Leaders, said: "Heads will balance the advice they receive against the budgets they manage."