Campaigners say an increased number of complaints to Suffolk County Council's SEND (special educational needs and disabilities) support team is the "tip of the iceberg" when it comes to problems faced by families.
The council acknowledges the situation but says it is working hard to make reforms.
The council has come under fire after statistics show that the number of complaints lodged against the Suffolk SEND provision are above those of the last two years in eight of the last twelve months.
Campaign for Change (Suffolk SEND) are a group of parents and carers of children and adults with additional needs, and in a statement a spokesperson condemned Suffolk County Council.
The spokesperson said: "These figures do not surprise us.
"It is little wonder that many parents complain, with their children seriously suffering the lack of education and the consequent harmful effects that this has. Given the desperate circumstances they find themselves in, many families do not have time or energy to navigate the council's bureaucratic barriers.
"The complaint figures we see today are just the tip of a huge iceberg in Suffolk."
A child may require special educational needs if a learning difficulty or disability means that they require additional or different support than other children.
Cabinet member for education, SEND and skills, councillor Rachel Hood has responded to the figures, and said: "Complaints regarding SEND provision in Suffolk have been high and, of course, I accept that this is not good enough.
“We noticed an increase in the number of complaints earlier in the year and, as I was newly appointed to this role at that time, we swiftly commissioned an independent review to look at a number of elements of our SEND services.
“This review was carried out by a team from Lincolnshire County Council who made a number of recommendations. We are now working hard to implements those recommendations and reform the way we do things.
“We accept we have a long way to go, but I am very encouraged by the pace and level of change we are already seeing.”
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