The committee, which is conducting a short investigation of special needs, heard from John Wright, a special needs lobbyist, that teachers who may provide vital evidence for a child are put under pressure."They are having some pretty nasty things said to them," said Mr Wright of the independent panel for special educational advice. "The authority is saying don't attend."
Adrian Faupel, from the Association of Educational Psychologists, told the committee that the tribunal system could hurt disadvantaged children because they have no one to act on their behalf.
There has been no appeal to the tribunal from children in local authority care, he said.
The committee was told by all its special education witnesses that SEN co-ordinators need more time to do their job properly.
"The co-ordinator is key to the Code of Practice," said Mr Faupel. "We are extremely worried about the burdens placed on them."
Vincent McDonnell, from the Society of Education Officers, said that some schools spend SEN money on inappropriate things.
This was a preliminary finding from an investigation of special needs conducted jointly by the SEO and Coopers and Lybrand.